diff --git a/.github/workflows/autoconf.yml b/.github/workflows/autoconf.yml
deleted file mode 100644
index abad8450..00000000
--- a/.github/workflows/autoconf.yml
+++ /dev/null
@@ -1,24 +0,0 @@
-# Checks that autoconf has been run if configure.ac was updated
-# Assumes that autoconf 2.71 was run, the same as ubuntu 22.04
-name: Autoconf Up To Date
-on:
-  pull_request:
-  workflow_dispatch:
-  push:
-jobs:
-  autoconf:
-    runs-on: 'ubuntu-22.04'
-
-    steps:
-      - name: deps
-        run: |
-          sudo apt-get -y update
-          sudo apt-get -y install autoconf
-
-      - uses: actions/checkout@v6
-
-      - name: run autoconf
-        run: autoconf && autoheader
-
-      - name: check no difference
-        run: git diff --exit-code
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 08b0096c..07424ee2 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,14 +6,17 @@ on:
   pull_request:
   workflow_dispatch:
   push:
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    steps:
-      - name: for pass test
-        run: |
-          echo "This is a test to check that the workflow is working. If you see this, the workflow is running and you can add more steps to it."
+    branches:
+      - main
+      - master
+
+# Avoid duplicate push + pull_request runs on PR branches, and cancel
+# superseded runs when new commits are pushed.
+concurrency:
+  group: buildtest-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 
+jobs:
   build:
     runs-on: ${{ matrix.os || 'ubuntu-24.04' }}
     strategy:
@@ -28,85 +31,93 @@ jobs:
 
         # MULTI and NOWRITEV are passed as integers to the build
         include:
-          # - name: plain linux
-          #   upload_sizes: 1
-
-          # - name: multi binary
-          #   multi: 1
-          #   multilink: 1
-
-          # - name: multi binary, dropbearmulti argv0
-          #   multi: 1
-          #   multiwrapper: 1
-
-          # - name: client only
-          #   runcheck: 'no'
-          #   make_target: PROGRAMS=dbclient
-
-          # - name: server only
-          #   runcheck: 'no'
-          #   make_target: PROGRAMS=dropbear
-
-          # - name: bundled libtom, 22.04, no writev()
-          #   # test can use an older distro with bundled libtommath
-          #   os: ubuntu-22.04
-          #   configure_flags: --enable-bundled-libtom --enable-werror
-          #   # NOWRITEV is unrelated, test here to save a job
-          #   nowritev: 1
-          #   # our tests expect >= python3.7
-          #   runcheck: 'no'
-
-          # - name: linux clang
-          #   cc: clang
+          - name: plain linux
+            upload_sizes: 1
+
+          - name: multi binary
+            multi: 1
+            multilink: 1
+
+          - name: multi binary, dropbearmulti argv0
+            multi: 1
+            multiwrapper: 1
+
+          - name: client only
+            runcheck: 'no'
+            make_target: PROGRAMS=dbclient
+
+          - name: server only
+            runcheck: 'no'
+            make_target: PROGRAMS=dropbear
+
+          - name: bundled libtom, 22.04, no writev()
+            # test can use an older distro with bundled libtommath
+            os: ubuntu-22.04
+            configure_flags: --enable-bundled-libtom --enable-werror
+            # NOWRITEV is unrelated, test here to save a job
+            nowritev: 1
+            # our tests expect >= python3.7
+            runcheck: 'no'
+
+          - name: linux clang
+            cc: clang
 
           # Some platforms only have old compilers, we try to keep
           # compatibilty. For some reason -std=c89 doesn't enforce
           # early declarations so we specify it anyway.
-          # - name: c89
-          #   extracflags: -std=c89 -Wdeclaration-after-statement
-          #   # enable all options
-          #   nondefault: 1
-          #   configure_flags: --enable-pam
-          #   # sntrup761.c is not c89 compliant
-          #   localoptions: |
-          #     #define DROPBEAR_SNTRUP761 0
-          #     #define DROPBEAR_MLKEM768 0
-
-          # - name: macos 14
-          #   os: macos-14
-          #   cc: clang
-          #   # OS X says daemon() and utmp are deprecated.
-          #   # OS X tests for undefined TARGET_OS_EMBEDDED in libc headers
-          #   extracflags: -Wno-deprecated-declarations -Wno-undef
-          #   runcheck: 'no'
-          #   apt: 'no'
-          #   # fails with:
-          #   # .../ranlib: file: libtomcrypt.a(cbc_setiv.o) has no symbols
-          #   ranlib: ranlib -no_warning_for_no_symbols
-
-          # - name: macos 15
-          #   os: macos-15
-          #   cc: clang
-          #   # OS X says daemon() and utmp are deprecated.
-          #   # OS X tests for undefined TARGET_OS_EMBEDDED in libc headers
-          #   extracflags: -Wno-deprecated-declarations -Wno-undef
-          #   runcheck: 'no'
-          #   apt: 'no'
-          #   # fails with:
-          #   # .../ranlib: file: libtomcrypt.a(cbc_setiv.o) has no symbols
-          #   ranlib: ranlib -no_warning_for_no_symbols
+          - name: c89
+            extracflags: -std=c89 -Wdeclaration-after-statement
+            # enable all options
+            nondefault: 1
+            configure_flags: --enable-pam
+            # sntrup761.c is not c89 compliant
+            localoptions: |
+              #define DROPBEAR_SNTRUP761 0
+              #define DROPBEAR_MLKEM768 0
+
+          - name: macos 14
+            os: macos-14
+            cc: clang
+            # OS X says daemon() and utmp are deprecated.
+            # OS X tests for undefined TARGET_OS_EMBEDDED in libc headers
+            extracflags: -Wno-deprecated-declarations -Wno-undef
+            runcheck: 'no'
+            apt: 'no'
+            # fails with:
+            # .../ranlib: file: libtomcrypt.a(cbc_setiv.o) has no symbols
+            ranlib: ranlib -no_warning_for_no_symbols
+            # macos doesn't have setresgid
+            localoptions: |
+              #define DROPBEAR_SVR_DROP_PRIVS 0
+              #define DROPBEAR_SVR_LOCALSTREAMFWD 0
+
+          - name: macos 15
+            os: macos-15
+            cc: clang
+            # OS X says daemon() and utmp are deprecated.
+            # OS X tests for undefined TARGET_OS_EMBEDDED in libc headers
+            extracflags: -Wno-deprecated-declarations -Wno-undef
+            runcheck: 'no'
+            apt: 'no'
+            # fails with:
+            # .../ranlib: file: libtomcrypt.a(cbc_setiv.o) has no symbols
+            ranlib: ranlib -no_warning_for_no_symbols
+            # macos doesn't have setresgid
+            localoptions: |
+              #define DROPBEAR_SVR_DROP_PRIVS 0
+              #define DROPBEAR_SVR_LOCALSTREAMFWD 0
 
           # Check that debug code doesn't bitrot
-          # - name: DEBUG_TRACE
-          #   nondefault: 1
-          #   configure_flags: --enable-pam
-          #   localoptions: |
-          #     #define DEBUG_TRACE 5
+          - name: DEBUG_TRACE
+            nondefault: 1
+            configure_flags: --enable-pam
+            localoptions: |
+              #define DEBUG_TRACE 5
 
           # Check off-by-default options don't bitrot
-          # - name: nondefault options
-          #   nondefault: 1
-          #   configure_flags: --enable-pam
+          - name: nondefault options
+            nondefault: 1
+            configure_flags: --enable-pam
 
           - name: most options disabled
             configure_flags: --disable-harden --disable-zlib --disable-openpty --disable-lastlog
@@ -145,25 +156,25 @@ jobs:
               #define DROPBEAR_USE_PASSWORD_ENV 0
               #define DROPBEAR_SFTPSERVER 0
 
-          # - name: no sha1
-          #   runcheck: 'no'
-          #   # disables all sha1
-          #   localoptions: |
-          #     #define DROPBEAR_SHA1_HMAC 0
-          #     #define DROPBEAR_RSA_SHA1 0
-          #     #define DROPBEAR_DH_GROUP14_SHA1 0
-          #     #define DROPBEAR_ECDSA 0
-          #     #define DROPBEAR_ED25519 0
-          #     #define DROPBEAR_SK_KEYS 0
-          #     #define DROPBEAR_ENABLE_GCM_MODE 1
-          #     #define DROPBEAR_3DES 1
-          #     #define DROPBEAR_DH_GROUP16 1
-          #     #define DROPBEAR_SHA2_512_HMAC 1
-          #     #define DROPBEAR_CLI_PUBKEY_AUTH 0
-
-          # - name: pq, no plain x25519
-          #   localoptions: |
-          #     #define DROPBEAR_CURVE25519 0
+          - name: no sha1
+            runcheck: 'no'
+            # disables all sha1
+            localoptions: |
+              #define DROPBEAR_SHA1_HMAC 0
+              #define DROPBEAR_RSA_SHA1 0
+              #define DROPBEAR_DH_GROUP14_SHA1 0
+              #define DROPBEAR_ECDSA 0
+              #define DROPBEAR_ED25519 0
+              #define DROPBEAR_SK_KEYS 0
+              #define DROPBEAR_ENABLE_GCM_MODE 1
+              #define DROPBEAR_3DES 1
+              #define DROPBEAR_DH_GROUP16 1
+              #define DROPBEAR_SHA2_512_HMAC 1
+              #define DROPBEAR_CLI_PUBKEY_AUTH 0
+
+          - name: pq, no plain x25519
+            localoptions: |
+              #define DROPBEAR_CURVE25519 0
 
           # # Fuzzers run standalone. A bit superfluous with cifuzz, but
           # # good to run the whole corpus to keep it working.
@@ -228,7 +239,7 @@ jobs:
         if: ${{ matrix.nondefault }}
         run: |
           # Turn on anything that's off by default. Rough but seems sufficient
-          grep ' 0$' src/default_options.h | sed 's/0$/1/' >> localoptions.h
+          grep ' 0$' src/default_options.h | grep -v DROPBEAR_SVR_OTP_PASSWORD | sed 's/0$/1/' >> localoptions.h
           # PAM clashes with password
           echo "#define DROPBEAR_SVR_PASSWORD_AUTH 0" >> localoptions.h
           # 1 second timeout is too short
diff --git a/.github/workflows/cifuzz.yml b/.github/workflows/cifuzz.yml
index 67a5d9d4..ae4ac94f 100644
--- a/.github/workflows/cifuzz.yml
+++ b/.github/workflows/cifuzz.yml
@@ -7,25 +7,29 @@ on:
   push:
     branches:
       - master
+# Cancel superseded runs on the same ref so pushes don't pile up.
+concurrency:
+  group: cifuzz-${{ github.ref }}
+  cancel-in-progress: true
 jobs:
   Fuzzing:
     runs-on: ubuntu-latest
     steps:
-    - name: Build Fuzzers
-      id: build
-      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
-      with:
-        oss-fuzz-project-name: 'dropbear'
-        dry-run: false
-    - name: Run Fuzzers
-      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
-      with:
-        oss-fuzz-project-name: 'dropbear'
-        fuzz-seconds: 1200
-        dry-run: false
-    - name: Upload Crash
-      uses: actions/upload-artifact@v4
-      if: failure() && steps.build.outcome == 'success'
-      with:
-        name: artifacts
-        path: ./out/artifacts
+      - name: Build Fuzzers
+        id: build
+        uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+        with:
+          oss-fuzz-project-name: "dropbear"
+          dry-run: false
+      - name: Run Fuzzers
+        uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+        with:
+          oss-fuzz-project-name: "dropbear"
+          fuzz-seconds: 300
+          dry-run: false
+      - name: Upload Crash
+        uses: actions/upload-artifact@v4
+        if: failure() && steps.build.outcome == 'success'
+        with:
+          name: artifacts
+          path: ./out/artifacts
diff --git a/.github/workflows/outoftree.yml b/.github/workflows/outoftree.yml
deleted file mode 100644
index 78020e2f..00000000
--- a/.github/workflows/outoftree.yml
+++ /dev/null
@@ -1,24 +0,0 @@
-# Can be used locally with https://github.com/nektos/act
-
-name: Out of tree build
-on:
-  pull_request:
-  workflow_dispatch:
-  push:
-jobs:
-  outoftree:
-    runs-on: 'ubuntu-22.04'
-
-    steps:
-      - uses: actions/checkout@v6
-
-      - name: build
-        run: |
-          mkdir build
-          cd build
-          ../configure --enable-fuzz --enable-bundled-libtom --prefix=$PWD/inst
-          make -j3
-          make -j3 fuzzstandalone
-          make install
-          test -x inst/bin/dbclient
-          test -f inst/share/man/man8/dropbear.8
diff --git a/.github/workflows/release-zig.yml b/.github/workflows/release-zig.yml
new file mode 100644
index 00000000..6abbf25c
--- /dev/null
+++ b/.github/workflows/release-zig.yml
@@ -0,0 +1,173 @@
+name: Release (zig build)
+
+# Builds dropbearmulti with `zig build` and publishes cross-compiled binaries.
+# Triggered by tags like `zig/v2025.88` (use `-alpha`/`-beta` suffixes for pre-releases).
+on:
+  push:
+    tags:
+      - "zig/v*"
+  workflow_dispatch:
+    inputs:
+      version:
+        description: "Version to build (e.g. v2025.88), no release is published"
+        required: false
+        default: "v0.0.0-dev"
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: Build ${{ matrix.label }}
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - runner: ubuntu-latest
+            target: x86_64-linux-musl
+            label: linux_amd64
+          - runner: ubuntu-latest
+            target: aarch64-linux-musl
+            label: linux_arm64
+          - runner: ubuntu-latest
+            target: arm-linux-musleabihf
+            label: linux_armv7
+          - runner: macos-latest
+            target: x86_64-macos
+            label: darwin_amd64
+          - runner: macos-latest
+            target: aarch64-macos
+            label: darwin_arm64
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install Zig
+        uses: mlugg/setup-zig@v2
+        with:
+          version: 0.16.0
+
+      - name: Cache Zig build artifacts
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cache/zig
+            .zig-cache
+          key: dropbear-${{ matrix.target }}-${{ hashFiles('build.zig', 'build.zig.zon') }}
+          restore-keys: |
+            dropbear-${{ matrix.target }}-
+
+      - name: Parse version and channel
+        id: version
+        shell: bash
+        run: |
+          if [[ "${GITHUB_REF}" == refs/tags/zig/* ]]; then
+            version="${GITHUB_REF#refs/tags/zig/}"
+          else
+            version="${{ github.event.inputs.version }}"
+          fi
+          echo "version=${version}" >> "$GITHUB_OUTPUT"
+          if [[ "$version" =~ -alpha ]]; then
+            echo "channel=dev" >> "$GITHUB_OUTPUT"
+          elif [[ "$version" =~ -beta ]]; then
+            echo "channel=beta" >> "$GITHUB_OUTPUT"
+          else
+            echo "channel=prod" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Build dropbearmulti
+        shell: bash
+        run: |
+          channel="${{ steps.version.outputs.channel }}"
+          if [[ "$channel" == "prod" ]]; then
+            optimize="ReleaseSmall"
+          else
+            optimize="ReleaseSafe"
+          fi
+          echo "Channel: ${channel}, Optimize: ${optimize}, Target: ${{ matrix.target }}"
+          if [[ "${{ matrix.target }}" == *-macos ]]; then
+            # Cross-compile both macOS arches on the arm64 runner using
+            # the universal macOS SDK so system headers like <util.h>
+            # resolve (an explicit -Dtarget disables zig's auto SDK
+            # detection, so we pass --sysroot explicitly).
+            zig build -Doptimize="${optimize}" -Dtarget="${{ matrix.target }}" --sysroot "$(xcrun --show-sdk-path)"
+          else
+            zig build -Doptimize="${optimize}" -Dtarget="${{ matrix.target }}"
+          fi
+
+      - name: Build sftp-server (Linux only)
+        if: startsWith(matrix.runner, 'ubuntu')
+        shell: bash
+        run: |
+          ./build-sftp-server.sh "${{ matrix.target }}" zig-out/bin
+
+      - name: Package archive
+        id: package
+        shell: bash
+        run: |
+          version="${{ steps.version.outputs.version }}"
+          archive="dropbear_${version}_${{ matrix.label }}.tar.gz"
+          mkdir -p release-artifacts
+          # Bundle dropbearmulti plus sftp-server (Linux) if present.
+          files="dropbearmulti"
+          [ -f zig-out/bin/sftp-server ] && files="$files sftp-server"
+          tar -czf "release-artifacts/${archive}" -C zig-out/bin $files
+          echo "archive=${archive}" >> "$GITHUB_OUTPUT"
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: dropbear-${{ matrix.label }}
+          path: release-artifacts/*.tar.gz
+          retention-days: 7
+
+  release:
+    name: Publish release
+    needs: build
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/zig/')
+    steps:
+      - name: Parse version and channel
+        id: version
+        shell: bash
+        run: |
+          version="${GITHUB_REF#refs/tags/zig/}"
+          echo "version=${version}" >> "$GITHUB_OUTPUT"
+          if [[ "$version" =~ -alpha ]]; then
+            echo "channel=dev" >> "$GITHUB_OUTPUT"
+          elif [[ "$version" =~ -beta ]]; then
+            echo "channel=beta" >> "$GITHUB_OUTPUT"
+          else
+            echo "channel=prod" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: dist
+          merge-multiple: true
+
+      - name: Generate checksums
+        shell: bash
+        run: |
+          cd dist
+          sha256sum *.tar.gz > checksums.txt
+          cat checksums.txt
+
+      - name: Create GitHub Release
+        env:
+          GH_TOKEN: ${{ secrets.RELEASER_TOKEN || secrets.GITHUB_TOKEN }}
+        shell: bash
+        run: |
+          prerelease=""
+          if [[ "${{ steps.version.outputs.channel }}" != "prod" ]]; then
+            prerelease="--prerelease"
+          fi
+          gh release create "${{ github.ref_name }}" \
+            --repo "${{ github.repository }}" \
+            --title "dropbear ${{ steps.version.outputs.version }}" \
+            --generate-notes \
+            $prerelease \
+            dist/*
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
deleted file mode 100644
index e6973e81..00000000
--- a/.github/workflows/release.yml
+++ /dev/null
@@ -1,59 +0,0 @@
-name: Release
-on:
-  push:
-    tags:
-      - 'v*.*.*'
-
-jobs:    
-  release:
-    name: Release on GitHub
-    runs-on: ubuntu-24.04
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
-      - name: Get Release Version
-        run: echo "RELEASE_VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
-
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v2
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-
-      - name: Build arm binaries
-        run: |
-          sh build.sh arm
-
-      - name: Build arm64 binaries
-        run: |
-          sh build.sh arm64
-
-      - name: Archives & Checksum
-        id: archives
-        run: |
-          sh ./package.sh "${{ env.RELEASE_VERSION }}" 
-
-      - name: Release
-        uses: softprops/action-gh-release@v2
-        id: create_release
-        if: github.ref_type == 'tag'
-        with:
-          generate_release_notes: true
-          files: |
-            ${{ env.RELEASE_VERSION }}-linux-arm.tar.gz
-            ${{ env.RELEASE_VERSION }}-linux-arm_checksums.txt
-            ${{ env.RELEASE_VERSION }}-linux-arm64.tar.gz
-            ${{ env.RELEASE_VERSION }}-linux-arm64_checksums.txt
-
-      - name: Notify Slack
-        uses: rtCamp/action-slack-notify@v2
-        env:
-          SLACK_CHANNEL: team-release
-          SLACK_COLOR: ${{ job.status }} # or a specific color like 'good' or '#ff00ff'
-          SLACK_ICON: "https://a.slack-edge.com/production-standard-emoji-assets/14.0/apple-medium/1f4ac@2x.png"
-          SLACK_MESSAGE: "${{ github.event.repository.name }} ${{ env.RELEASE_VERSION }} is out! Check it out at ${{ steps.create_release.outputs.url }}"
-          SLACK_TITLE: "${{ github.event.repository.name }} ${{ env.RELEASE_VERSION }} Release"
-          SLACK_USERNAME: release
-          SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
diff --git a/.github/workflows/tarball.yml b/.github/workflows/tarball.yml
deleted file mode 100644
index f3c5f294..00000000
--- a/.github/workflows/tarball.yml
+++ /dev/null
@@ -1,36 +0,0 @@
-name: tarball sha256sum
-on:
-  push:
-    branches:
-      - master
-jobs:
-  tarball:
-    runs-on: 'ubuntu-22.04'
-
-    steps:
-      - uses: actions/checkout@v6
-
-      - name: release.sh
-        run: ./release.sh --testrel | tee log1.txt
-
-      - name: extract output
-        run: |
-          grep ^SHA256 log1.txt | tee sha256sum.txt
-          sed 's/.*= *//' < sha256sum.txt > hash.txt
-          mv `tail -n1 log1.txt` rel.tar.bz2
-
-      - name: sha256sum
-        uses: actions/upload-artifact@v7
-        with:
-          name: sha256sum
-          path: |
-            sha256sum.txt
-            hash.txt
-
-      - name: tarball
-        uses: actions/upload-artifact@v7
-        with:
-          name: tarball
-          # only keep for debugging
-          retention-days: 3
-          path: rel.tar.bz2
diff --git a/.gitignore b/.gitignore
index c62a46b0..f11d8e57 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,3 +33,7 @@ tags
 .vscode/
 .DS_Store
 build/
+.local
+.idea
+/.zig-cache/
+/zig-out/
\ No newline at end of file
diff --git a/Dockerfile b/Dockerfile
deleted file mode 100644
index 8e6ec108..00000000
--- a/Dockerfile
+++ /dev/null
@@ -1,68 +0,0 @@
-ARG baseImg=arm64v8/alpine:3.20
-
-FROM ${baseImg}
-
-RUN apk add --no-cache \
-    bash \
-    build-base \
-    git \
-    wget \
-    autoconf \
-    automake \
-    libtool \
-    pkgconf \
-    coreutils \
-    bzip2 \
-    linux-headers \
-    openssl-dev \
-    openssl-libs-static \
-    zlib-dev \
-    zlib-static \
-    perl \
-    m4
-
-WORKDIR /app
-
-ENV TARGET=aarch64-alpine-linux-musl \
-    CC="gcc -static" \
-    CFLAGS="-Os -ffunction-sections -fdata-sections -fno-exceptions -fno-rtti" \
-    LDFLAGS="-static -Wl,--gc-sections -Wl,--strip-all"
-
-RUN git clone https://github.com/openssh/openssh-portable --depth=1
-WORKDIR /app/openssh-portable
-
-RUN autoreconf && \
-    ./configure \
-    --host=${TARGET} \
-    --disable-server \
-    --disable-strip \
-    --disable-pkcs11 \
-    --disable-security-key \
-    --without-openssl \
-    --without-zlib-version-check \
-    --without-openssl-header-check \
-    --with-sandbox=no \
-    --with-pam=no \
-    --with-selinux=no \
-    --with-kerberos5=no \
-    --with-libedit=no \
-    --with-ldns=no \
-    CC="${CC}" \
-    CFLAGS="${CFLAGS}" \
-    LDFLAGS="${LDFLAGS}" \
-    LIBS="-static -lz -lcrypto -lssl"
-    
-RUN make -j"$(nproc)"
-
-WORKDIR /app
-
-ADD . /app
-
-ENV DROPBEAR_VERSION=2024.86
-
-# ENV LDFLAGS=-static-libgcc
-# ENV CFLAGS="-ffunction-sections -fdata-sections"
-# ENV LTM_CFLAGS=-Os
-
-RUN ./configure --host=${TARGET} --enable-static CC="${CC}" CFLAGS="${CFLAGS}" LDFLAGS="${LDFLAGS}"
-RUN make -j"$(nproc)" PROGRAMS="dropbear dbclient dropbearkey dropbearconvert scp" MULTI=1
diff --git a/README.md b/README.md
index bb3f6ed6..2457539d 100644
--- a/README.md
+++ b/README.md
@@ -90,3 +90,57 @@ Get the binary at `./build`
 1. `sh build.sh arm`
 ### arm64
 1. `sh build.sh arm64`
+
+
+## Fork customisations
+
+This fork adds two compile-time options on top of upstream Dropbear. Both are
+configured in `default_options.h` (or in a `localoptions.h` in the build dir)
+and keep upstream behaviour unless you change them.
+
+### Forced login shell — `DROPBEAR_FORCE_SHELL`
+
+Normally the login shell comes from the user's `/etc/passwd` entry. Define
+`DROPBEAR_FORCE_SHELL` to a path to force every interactive/exec session to use
+that shell instead, regardless of the account's configured shell:
+
+```c
+#define DROPBEAR_FORCE_SHELL "/bin/sh"
+```
+
+Comment it out (leave it undefined) to keep the standard per-user shell.
+
+### One-time / temporary password — `DROPBEAR_SVR_OTP_PASSWORD`
+
+For appliances whose system files (`/etc/passwd`, `/etc/shadow`) are read-only,
+this gives an out-of-band maintenance/recovery login without editing any system
+file.
+
+Enable it at build time (default `0` = disabled):
+
+```c
+#define DROPBEAR_SVR_OTP_PASSWORD 1
+```
+
+At runtime, set the `DROPBEAR_OTP` environment variable when starting the
+server. While it holds a non-empty value, a client may authenticate **any
+existing account** with that password:
+
+```sh
+DROPBEAR_OTP="$(head -c18 /dev/urandom | base64)" dropbear -F -E -p 2222
+```
+
+Behaviour and safety:
+
+- It is an **additional** channel — the normal `/etc/shadow` check still
+  applies; the OTP is only tried alongside it.
+- It works even for **locked** accounts (`!` / `*` in shadow).
+- The password is **constant-time compared** and **never written to logs**
+  (a successful OTP login logs only `OTP auth succeeded for '<user>' from ...`).
+- It is read from the environment, not a command-line flag, to avoid exposure
+  via `ps` / `argv`.
+
+Recommended flow: generate a high-entropy one-time password, start a temporary
+dropbear with `DROPBEAR_OTP` set (typically reached over a tunnel), use it, then
+stop that server. Keep `DROPBEAR_SVR_OTP_PASSWORD` at `0` in builds that don't
+need it.
diff --git a/build-sftp-server.sh b/build-sftp-server.sh
new file mode 100755
index 00000000..f6c93b1a
--- /dev/null
+++ b/build-sftp-server.sh
@@ -0,0 +1,68 @@
+#!/bin/sh
+# Cross-compile OpenSSH's sftp-server using `zig cc` as the C compiler.
+#
+# Dropbear's server execs an external sftp-server binary for the SFTP subsystem;
+# it does not ship one itself. This script produces a statically linked
+# sftp-server that can be bundled alongside dropbearmulti.
+#
+# Usage: build-sftp-server.sh <zig-target> <out-dir> [openssh-version]
+#   <zig-target>      e.g. x86_64-linux-musl, aarch64-linux-musl, arm-linux-musleabihf
+#   <out-dir>         directory to copy the resulting `sftp-server` into
+#   [openssh-version] OpenSSH portable version (default below)
+set -eu
+
+ZIG_TARGET="${1:?usage: build-sftp-server.sh <zig-target> <out-dir> [openssh-version]}"
+OUT_DIR="${2:?usage: build-sftp-server.sh <zig-target> <out-dir> [openssh-version]}"
+OPENSSH_VERSION="${3:-9.9p2}"
+
+# Use the zig target triple directly as the autoconf --host so configure runs in
+# cross-compile mode; zig cc performs the actual codegen via -target.
+HOST="$ZIG_TARGET"
+
+# Resolve OUT_DIR to an absolute path now, before we cd into the (temporary)
+# OpenSSH build tree. Otherwise a relative path would resolve against that
+# temp dir and the copied binary would be deleted with it.
+mkdir -p "$OUT_DIR"
+OUT_DIR="$(cd "$OUT_DIR" && pwd)"
+
+workdir="$(mktemp -d)"
+trap 'rm -rf "$workdir"' EXIT
+
+tarball="openssh-${OPENSSH_VERSION}.tar.gz"
+url="https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/portable/${tarball}"
+echo "==> Downloading ${url}"
+curl -fsSL -o "$workdir/$tarball" "$url"
+tar -xzf "$workdir/$tarball" -C "$workdir"
+src="$workdir/openssh-${OPENSSH_VERSION}"
+
+cd "$src"
+
+# Avoid leaking the host toolchain's CPPFLAGS/CFLAGS/LDFLAGS into the cross build.
+unset CPPFLAGS CFLAGS LDFLAGS LIBS
+
+echo "==> Configuring OpenSSH for ${ZIG_TARGET}"
+./configure \
+    --host="$HOST" \
+    CC="zig cc -target $ZIG_TARGET" \
+    AR="zig ar" \
+    RANLIB="zig ranlib" \
+    --without-openssl \
+    --without-zlib \
+    --without-pam \
+    --without-selinux \
+    --without-kerberos5 \
+    --without-libedit \
+    --without-ldns \
+    --with-sandbox=no \
+    --disable-strip \
+    --disable-pkcs11 \
+    --disable-security-key \
+    CFLAGS="-Os -ffunction-sections -fdata-sections" \
+    LDFLAGS="-static -s -Wl,--gc-sections"
+
+echo "==> Building sftp-server"
+make sftp-server -j"$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 2)"
+
+mkdir -p "$OUT_DIR"
+cp sftp-server "$OUT_DIR/sftp-server"
+echo "==> Built $OUT_DIR/sftp-server"
diff --git a/build.sh b/build.sh
deleted file mode 100755
index 3eacd7f6..00000000
--- a/build.sh
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/bin/sh
-
-set -ex
-
-hardware=$1
-if [ -z "$hardware" ]; then
-  hardware="arm64"
-fi
-
-platform=""
-dockername=""
-docker_baseImg=""
-distdir=""
-if [ "$hardware" = "arm64" ]; then
-  # supported arm64-jetson arm64-spark arm64-axis
-  platform="linux/arm64/v8"
-  dockername="arm64v8-dropbear"
-  docker_baseImg="arm64v8/alpine:3.20"
-elif [ "$hardware" = "arm" ]; then
-  platform="linux/arm/v7"
-  dockername="arm32v7-dropbear"
-  docker_baseImg="arm32v7/alpine:3.20"
-elif [ "$hardware" = "x86_64" ]; then
-  platform="linux/amd64"
-  dockername="x86_64-dropbear"
-  docker_baseImg="amd64/alpine:3.20"
-else
-  echo "Unsupported hardware: $hardware"
-  echo "Supported hardware: arm64, arm, x86_64"
-  exit 1
-fi
-
-distdir="build/$hardware"
-
-echo "Building for hardware: $hardware"
-echo "Using platform: $platform"
-echo "Using docker image name: $dockername"
-echo "Using docker build base image: $docker_baseImg"
-echo "Using distribution directory: $distdir"
-
-rm -rf "$distdir"
-
-mkdir -p "$distdir/bin"
-mkdir -p "$distdir/lib"
-mkdir -p "$distdir/include"
-
-docker build --platform=$platform -t $dockername  --build-arg baseImg=$docker_baseImg .
-
-docker run --platform=$platform --rm -v $(pwd)/build:/app/build $dockername cp ./dropbearmulti ./$distdir/bin/
-docker run --platform=$platform --rm -v $(pwd)/build:/app/build $dockername cp ./openssh-portable/sftp-server ./$distdir/bin/
-docker run --platform=$platform --rm -v $(pwd)/build:/app/build $dockername cp ./libtomcrypt/libtomcrypt.a ./$distdir/lib/
-
-cp -r ./libtomcrypt/src/headers/* ./$distdir/include
-
-cd $distdir/bin
-
-ln -s dropbearmulti dropbear
-ln -s dropbearmulti dbclient
-ln -s dropbearmulti dropbearkey
-ln -s dropbearmulti dropbearconvert
-ln -s dropbearmulti scp
diff --git a/build.zig b/build.zig
new file mode 100644
index 00000000..1dfe1acd
--- /dev/null
+++ b/build.zig
@@ -0,0 +1,480 @@
+const std = @import("std");
+
+// Dropbear build using `zig build` (Zig 0.16).
+//
+// This replaces the autoconf/Makefile build for producing release binaries.
+// It compiles the bundled libtommath and libtomcrypt as static libraries and
+// links them into a single multi-call `dropbearmulti` binary (containing the
+// dropbear server, dbclient, dropbearkey, dropbearconvert and scp applets).
+//
+// A target-appropriate `config.h` is generated at configure time so the build
+// works for cross-compilation (notably Linux/musl) without running ./configure.
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+    const upx = b.option(bool, "upx", "Compress the binary with UPX (requires upx in PATH)") orelse false;
+
+    const os_tag = target.result.os.tag;
+
+    // When cross-compiling to macOS (e.g. building x86_64 on an arm64 runner)
+    // the SDK is passed via `--sysroot $(xcrun --show-sdk-path)`. zig uses it
+    // for linking, but does NOT add the SDK's usr/include to the C header
+    // search path, so we add it explicitly (else <util.h> etc. won't resolve).
+    // No effect on Linux builds (b.sysroot is null there).
+    const macos_sdk: ?[]const u8 =
+        if ((os_tag == .macos or os_tag == .ios or os_tag == .tvos or os_tag == .watchos) and b.sysroot != null)
+            b.sysroot
+        else
+            null;
+
+    // ---- Generated headers ---------------------------------------------------
+    const wf = b.addWriteFiles();
+    const config_h = wf.add("config.h", genConfigH(b, os_tag));
+    _ = wf.add("default_options_guard.h", genGuard(b));
+    // Both generated files live in the same directory.
+    const gen_dir = config_h.dirname();
+
+    // Shared include directories for every translation unit.
+    const includes = [_]std.Build.LazyPath{
+        gen_dir,
+        b.path("src"),
+        b.path("libtomcrypt/src/headers"),
+        b.path("libtommath"),
+    };
+
+    // Common preprocessor / compiler flags.
+    var common_flags: std.ArrayList([]const u8) = .empty;
+    common_flags.appendSlice(b.allocator, &.{
+        "-std=gnu99",
+        "-fno-strict-aliasing",
+        "-Wno-pointer-sign",
+        // Emit per-function/data sections so the linker can garbage-collect
+        // unused code (e.g. libtomcrypt ciphers dropbear never references).
+        "-ffunction-sections",
+        "-fdata-sections",
+    }) catch @panic("OOM");
+    if (os_tag == .linux) {
+        // _GNU_SOURCE is a glibc/musl feature-test macro; macOS exposes the
+        // needed symbols by default and some sources self-define _GNU_SOURCE
+        // (which would clash with -D_GNU_SOURCE on macOS).
+        common_flags.append(b.allocator, "-D_GNU_SOURCE") catch @panic("OOM");
+        common_flags.append(b.allocator, "-D_FILE_OFFSET_BITS=64") catch @panic("OOM");
+    }
+
+    // ---- libtommath ----------------------------------------------------------
+    const ltm = b.addLibrary(.{
+        .name = "tommath",
+        .linkage = .static,
+        .root_module = b.createModule(.{
+            .target = target,
+            .optimize = optimize,
+            .link_libc = true,
+        }),
+    });
+    for (includes) |inc| ltm.root_module.addIncludePath(inc);
+    if (macos_sdk) |sdk| addMacosSdkInclude(b, ltm.root_module, sdk);
+    ltm.step.dependOn(&wf.step);
+    ltm.root_module.addCSourceFiles(.{
+        .root = b.path("."),
+        .files = collectCSources(b, "libtommath", false),
+        .flags = common_flags.items,
+    });
+
+    // ---- libtomcrypt ---------------------------------------------------------
+    var ltc_flags: std.ArrayList([]const u8) = .empty;
+    ltc_flags.appendSlice(b.allocator, common_flags.items) catch @panic("OOM");
+    ltc_flags.append(b.allocator, "-DLTC_SOURCE") catch @panic("OOM");
+
+    const ltc = b.addLibrary(.{
+        .name = "tomcrypt",
+        .linkage = .static,
+        .root_module = b.createModule(.{
+            .target = target,
+            .optimize = optimize,
+            .link_libc = true,
+        }),
+    });
+    for (includes) |inc| ltc.root_module.addIncludePath(inc);
+    if (macos_sdk) |sdk| addMacosSdkInclude(b, ltc.root_module, sdk);
+    ltc.step.dependOn(&wf.step);
+    ltc.root_module.addCSourceFiles(.{
+        .root = b.path("."),
+        .files = collectCSources(b, "libtomcrypt/src", true),
+        .flags = ltc_flags.items,
+    });
+
+    // ---- dropbearmulti -------------------------------------------------------
+    var db_flags: std.ArrayList([]const u8) = .empty;
+    db_flags.appendSlice(b.allocator, common_flags.items) catch @panic("OOM");
+    db_flags.appendSlice(b.allocator, &.{
+        "-DDROPBEAR_SERVER",
+        "-DDROPBEAR_CLIENT",
+        "-DDROPBEAR_MULTI",
+        "-DDBMULTI_dropbear",
+        "-DDBMULTI_dbclient",
+        "-DDBMULTI_dropbearkey",
+        "-DDBMULTI_dropbearconvert",
+        "-DDBMULTI_scp",
+        "-DPROGRESS_METER",
+    }) catch @panic("OOM");
+
+    const exe = b.addExecutable(.{
+        .name = "dropbearmulti",
+        .root_module = b.createModule(.{
+            .target = target,
+            .optimize = optimize,
+            .link_libc = true,
+            .strip = if (optimize != .Debug) true else null,
+        }),
+    });
+    for (includes) |inc| exe.root_module.addIncludePath(inc);
+    if (macos_sdk) |sdk| addMacosSdkInclude(b, exe.root_module, sdk);
+    exe.step.dependOn(&wf.step);
+    // Garbage-collect unreferenced sections produced by -ffunction/-fdata-sections.
+    exe.link_gc_sections = true;
+    exe.root_module.addCSourceFiles(.{
+        .root = b.path("src"),
+        .files = &dropbear_sources,
+        .flags = db_flags.items,
+    });
+    exe.root_module.linkLibrary(ltc);
+    exe.root_module.linkLibrary(ltm);
+
+    const install = b.addInstallArtifact(exe, .{});
+
+    if (upx) {
+        const upx_step = b.addSystemCommand(&.{
+            "upx",                                   "--best", "--lzma",
+            b.getInstallPath(.bin, "dropbearmulti"),
+        });
+        upx_step.step.dependOn(&install.step);
+        b.getInstallStep().dependOn(&upx_step.step);
+    } else {
+        b.getInstallStep().dependOn(&install.step);
+    }
+}
+
+// dropbear source files (relative to `src/`). This is the union of the object
+// lists in Makefile.in needed for a multi-call binary that bundles the server,
+// client, dropbearkey, dropbearconvert and scp.
+const dropbear_sources = [_][]const u8{
+    // dbmulti dispatcher
+    "dbmulti.c",
+    // COMMONOBJS
+    "dbutil.c",
+    "buffer.c",
+    "dbhelpers.c",
+    "dss.c",
+    "bignum.c",
+    "signkey.c",
+    "rsa.c",
+    "dbrandom.c",
+    "queue.c",
+    "atomicio.c",
+    "compat.c",
+    "fake-rfc2553.c",
+    "ltc_prng.c",
+    "ecc.c",
+    "ecdsa.c",
+    "sk-ecdsa.c",
+    "crypto_desc.c",
+    "curve25519.c",
+    "ed25519.c",
+    "sk-ed25519.c",
+    "dbmalloc.c",
+    "gensignkey.c",
+    "gendss.c",
+    "genrsa.c",
+    "gened25519.c",
+    // CLISVROBJS
+    "common-session.c",
+    "packet.c",
+    "common-algo.c",
+    "common-kex.c",
+    "common-channel.c",
+    "common-chansession.c",
+    "termcodes.c",
+    "loginrec.c",
+    "tcp-accept.c",
+    "listener.c",
+    "process-packet.c",
+    "dh_groups.c",
+    "common-runopts.c",
+    "circbuffer.c",
+    "list.c",
+    "netio.c",
+    "chachapoly.c",
+    "gcm.c",
+    "kex-x25519.c",
+    "kex-dh.c",
+    "kex-ecdh.c",
+    "kex-pqhybrid.c",
+    "sntrup761.c",
+    "mlkem768.c",
+    // SVROBJS
+    "svr-kex.c",
+    "svr-auth.c",
+    "sshpty.c",
+    "svr-authpasswd.c",
+    "svr-authpubkey.c",
+    "svr-authpubkeyoptions.c",
+    "svr-session.c",
+    "svr-service.c",
+    "svr-chansession.c",
+    "svr-runopts.c",
+    "svr-agentfwd.c",
+    "svr-main.c",
+    "svr-x11fwd.c",
+    "svr-forward.c",
+    "svr-tcpfwd.c",
+    "svr-streamfwd.c",
+    "svr-authpam.c",
+    // CLIOBJS
+    "cli-main.c",
+    "cli-auth.c",
+    "cli-authpasswd.c",
+    "cli-kex.c",
+    "cli-session.c",
+    "cli-runopts.c",
+    "cli-chansession.c",
+    "cli-authpubkey.c",
+    "cli-tcpfwd.c",
+    "cli-channel.c",
+    "cli-authinteract.c",
+    "cli-agentfwd.c",
+    "cli-readconf.c",
+    // KEYOBJS
+    "dropbearkey.c",
+    // CONVERTOBJS
+    "dropbearconvert.c",
+    "keyimport.c",
+    "signkey_ossh.c",
+    // SCPOBJS (atomicio.c / compat.c already present above)
+    "scp.c",
+    "progressmeter.c",
+    "scpmisc.c",
+};
+
+// Walk a directory under the build root and collect every `.c` file, returning
+// paths relative to the build root.
+fn collectCSources(b: *std.Build, comptime sub: []const u8, recursive: bool) [][]const u8 {
+    const io = b.graph.io;
+    var list: std.ArrayList([]const u8) = .empty;
+    var dir = b.build_root.handle.openDir(io, sub, .{ .iterate = true }) catch |err| {
+        std.debug.panic("failed to open {s}: {s}", .{ sub, @errorName(err) });
+    };
+    defer dir.close(io);
+
+    if (recursive) {
+        var walker = dir.walk(b.allocator) catch @panic("OOM");
+        defer walker.deinit();
+        while (walker.next(io) catch @panic("walk failed")) |entry| {
+            if (entry.kind != .file) continue;
+            if (!std.mem.endsWith(u8, entry.basename, ".c")) continue;
+            // *tab.c files in libtomcrypt are lookup tables that are #included
+            // by other sources, not compiled on their own.
+            if (std.mem.endsWith(u8, entry.basename, "tab.c")) continue;
+            const rel = std.fs.path.join(b.allocator, &.{ sub, entry.path }) catch @panic("OOM");
+            list.append(b.allocator, rel) catch @panic("OOM");
+        }
+    } else {
+        var it = dir.iterate();
+        while (it.next(io) catch @panic("iterate failed")) |entry| {
+            if (entry.kind != .file) continue;
+            if (!std.mem.endsWith(u8, entry.name, ".c")) continue;
+            const rel = std.fs.path.join(b.allocator, &.{ sub, entry.name }) catch @panic("OOM");
+            list.append(b.allocator, rel) catch @panic("OOM");
+        }
+    }
+    return list.toOwnedSlice(b.allocator) catch @panic("OOM");
+}
+
+// Add the macOS SDK's system header directory so cross-compiling (e.g. x86_64
+// on an arm64 runner) can resolve system headers like <util.h>. Linking is
+// handled by --sysroot, so only the include path is added here.
+fn addMacosSdkInclude(b: *std.Build, m: *std.Build.Module, sdk: []const u8) void {
+    m.addSystemIncludePath(.{ .cwd_relative = b.pathJoin(&.{ sdk, "usr", "include" }) });
+}
+
+// Generate default_options_guard.h from src/default_options.h by wrapping every
+// `#define X Y` in an `#ifndef X ... #endif` guard (equivalent to
+// src/ifndef_wrapper.sh). The guards let the generated config.h override any
+// default (e.g. disabling DROPBEAR_SVR_DROP_PRIVS on platforms without
+// setresgid()).
+fn genGuard(b: *std.Build) []const u8 {
+    const io = b.graph.io;
+    const input = b.build_root.handle.readFileAlloc(
+        io,
+        "src/default_options.h",
+        b.allocator,
+        .unlimited,
+    ) catch |err| {
+        std.debug.panic("failed to read default_options.h: {s}", .{@errorName(err)});
+    };
+
+    var out: std.ArrayList(u8) = .empty;
+    out.appendSlice(
+        b.allocator,
+        "/* Generated by build.zig from default_options.h - do not edit */\n",
+    ) catch @panic("OOM");
+
+    var it = std.mem.splitScalar(u8, input, '\n');
+    while (it.next()) |line| {
+        if (definedName(line)) |name| {
+            const wrapped = std.fmt.allocPrint(
+                b.allocator,
+                "#ifndef {s}\n{s}\n#endif\n",
+                .{ name, line },
+            ) catch @panic("OOM");
+            out.appendSlice(b.allocator, wrapped) catch @panic("OOM");
+        } else {
+            out.appendSlice(b.allocator, line) catch @panic("OOM");
+            out.append(b.allocator, '\n') catch @panic("OOM");
+        }
+    }
+    return out.toOwnedSlice(b.allocator) catch @panic("OOM");
+}
+
+// Returns the macro name if `line` is `<spaces>#define <NAME> <value...>`.
+fn definedName(line: []const u8) ?[]const u8 {
+    var s = line;
+    while (s.len > 0 and (s[0] == ' ' or s[0] == '\t')) s = s[1..];
+    const prefix = "#define ";
+    if (!std.mem.startsWith(u8, s, prefix)) return null;
+    s = s[prefix.len..];
+    while (s.len > 0 and (s[0] == ' ' or s[0] == '\t')) s = s[1..];
+    var i: usize = 0;
+    while (i < s.len and s[i] != ' ' and s[i] != '\t') i += 1;
+    if (i == 0) return null;
+    // Require a value after the name (matching the sed `.* ` semantics).
+    if (i >= s.len) return null;
+    return s[0..i];
+}
+
+fn genConfigH(b: *std.Build, os_tag: std.Target.Os.Tag) []const u8 {
+    var out: std.ArrayList(u8) = .empty;
+    out.appendSlice(b.allocator, common_config) catch @panic("OOM");
+    switch (os_tag) {
+        .macos, .ios, .tvos, .watchos => out.appendSlice(b.allocator, macos_config) catch @panic("OOM"),
+        else => out.appendSlice(b.allocator, linux_config) catch @panic("OOM"),
+    }
+    out.appendSlice(b.allocator, "\n#endif /* DROPBEAR_CONFIG_H */\n") catch @panic("OOM");
+    return out.toOwnedSlice(b.allocator) catch @panic("OOM");
+}
+
+const common_config =
+    \\/* Generated by build.zig - do not edit */
+    \\#ifndef DROPBEAR_CONFIG_H
+    \\#define DROPBEAR_CONFIG_H
+    \\
+    \\#define BUNDLED_LIBTOM 1
+    \\#define DROPBEAR_FUZZ 0
+    \\#define DROPBEAR_PLUGIN 0
+    \\
+    \\/* Login recording is disabled for the portable zig build. */
+    \\#define DISABLE_PAM 1
+    \\#define DISABLE_ZLIB 1
+    \\#define DISABLE_LASTLOG 1
+    \\#define DISABLE_UTMP 1
+    \\#define DISABLE_UTMPX 1
+    \\#define DISABLE_WTMP 1
+    \\#define DISABLE_WTMPX 1
+    \\
+    \\#define HAVE_BASENAME 1
+    \\#define HAVE_CLOCK_GETTIME 1
+    \\#define HAVE_CONST_GAI_STRERROR_PROTO 1
+    \\#define HAVE_CRYPT 1
+    \\#define HAVE_DAEMON 1
+    \\#define HAVE_FORK 1
+    \\#define HAVE_FREEADDRINFO 1
+    \\#define HAVE_GAI_STRERROR 1
+    \\#define HAVE_GETADDRINFO 1
+    \\#define HAVE_GETGROUPLIST 1
+    \\#define HAVE_GETNAMEINFO 1
+    \\#define HAVE_GETPASS 1
+    \\#define HAVE_GETUSERSHELL 1
+    \\#define HAVE_INTTYPES_H 1
+    \\#define HAVE_LIBGEN_H 1
+    \\#define HAVE_NETDB_H 1
+    \\#define HAVE_NETINET_IN_H 1
+    \\#define HAVE_NETINET_IN_SYSTM_H 1
+    \\#define HAVE_NETINET_TCP_H 1
+    \\#define HAVE_PATHS_H 1
+    \\#define HAVE_PUTENV 1
+    \\#define HAVE_STDINT_H 1
+    \\#define HAVE_STDIO_H 1
+    \\#define HAVE_STDLIB_H 1
+    \\#define HAVE_STRINGS_H 1
+    \\#define HAVE_STRING_H 1
+    \\#define HAVE_STRUCT_ADDRINFO 1
+    \\#define HAVE_STRUCT_IN6_ADDR 1
+    \\#define HAVE_STRUCT_SOCKADDR_IN6 1
+    \\#define HAVE_STRUCT_SOCKADDR_STORAGE 1
+    \\#define HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY 1
+    \\#define HAVE_SYS_RANDOM_H 1
+    \\#define HAVE_SYS_SELECT_H 1
+    \\#define HAVE_SYS_SOCKET_H 1
+    \\#define HAVE_SYS_STAT_H 1
+    \\#define HAVE_SYS_TYPES_H 1
+    \\#define HAVE_SYS_UIO_H 1
+    \\#define HAVE_SYS_WAIT_H 1
+    \\#define HAVE_UINT16_T 1
+    \\#define HAVE_UINT32_T 1
+    \\#define HAVE_UINT8_T 1
+    \\#define HAVE_UNDERSCORE_STATIC_ASSERT 1
+    \\#define HAVE_UNISTD_H 1
+    \\#define HAVE_U_INT16_T 1
+    \\#define HAVE_U_INT32_T 1
+    \\#define HAVE_U_INT8_T 1
+    \\#define HAVE_WRITEV 1
+    \\
+    \\#define SELECT_TYPE_ARG1 int
+    \\#define SELECT_TYPE_ARG234 (fd_set *)
+    \\#define SELECT_TYPE_ARG5 (struct timeval *)
+    \\#define STDC_HEADERS 1
+    \\
+    \\#define PACKAGE_NAME ""
+    \\#define PACKAGE_STRING ""
+    \\#define PACKAGE_TARNAME ""
+    \\#define PACKAGE_VERSION ""
+    \\#define PACKAGE_BUGREPORT ""
+    \\#define PACKAGE_URL ""
+    \\
+;
+
+const linux_config =
+    \\/* Linux / musl specific */
+    \\#define HAVE_CRYPT_H 1
+    \\#define HAVE_SHADOW_H 1
+    \\#define HAVE_GETSPNAM 1
+    \\#define HAVE_PTY_H 1
+    \\#define HAVE_OPENPTY 1
+    \\#define HAVE_ENDIAN_H 1
+    \\#define HAVE_DECL_HTOLE64 1
+    \\#define HAVE_SYS_PRCTL_H 1
+    \\#define HAVE_LINUX_PKT_SCHED_H 1
+    \\#define HAVE_CLEARENV 1
+    \\#define HAVE_FEXECVE 1
+    \\#define HAVE_EXPLICIT_BZERO 1
+    \\#define HAVE_SETRESGID 1
+    \\#define HAVE_GETRANDOM 1
+    \\
+;
+
+const macos_config =
+    \\/* macOS specific */
+    \\/* macOS has no <sys/endian.h>; dropbear's compat.c provides htole64/le64toh
+    \\   (left undefined here so HAVE_DECL_HTOLE64 stays off). */
+    \\#define HAVE_MACH_ABSOLUTE_TIME 1
+    \\#define HAVE_MACH_MACH_TIME_H 1
+    \\#define HAVE_MEMSET_S 1
+    \\#define HAVE_OPENPTY 1
+    \\#define HAVE_UTIL_H 1
+    \\#define HAVE_STRLCAT 1
+    \\#define HAVE_STRLCPY 1
+    \\/* macOS/BSD lack setresgid(); disable server privilege dropping that needs it. */
+    \\#define DROPBEAR_SVR_MULTIUSER 0
+    \\#define DROPBEAR_SVR_DROP_PRIVS 0
+    \\
+;
diff --git a/build.zig.zon b/build.zig.zon
new file mode 100644
index 00000000..ae4fdc42
--- /dev/null
+++ b/build.zig.zon
@@ -0,0 +1,14 @@
+.{
+    .name = .dropbear,
+    .version = "2025.88.0",
+    .minimum_zig_version = "0.16.0",
+    .dependencies = .{},
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "src",
+        "libtomcrypt",
+        "libtommath",
+    },
+    .fingerprint = 0x57da91df300bdbc5,
+}
diff --git a/src/bignum.c b/src/bignum.c
index ecccaa0b..c09f7556 100644
--- a/src/bignum.c
+++ b/src/bignum.c
@@ -104,6 +104,8 @@ void hash_process_mp(const struct ltc_hash_descriptor *hash_desc,
 }
 
 void m_mp_burn(mp_int *mp) {
-	m_burn(mp->dp, mp->alloc * sizeof(*mp->dp));
+	if (mp->dp) {
+		m_burn(mp->dp, mp->alloc * sizeof(*mp->dp));
+	}
 	mp->used = 0;
 }
diff --git a/src/cli-runopts.c b/src/cli-runopts.c
index de931f4f..be768704 100644
--- a/src/cli-runopts.c
+++ b/src/cli-runopts.c
@@ -676,6 +676,7 @@ static char** multihop_args(const char* argv0, const char* prior_hops) {
 	args[pos] = m_strdup(prior_hops);
 	pos++;
 
+	args[pos] = NULL;
 	return args;
 }
 
diff --git a/src/common-session.c b/src/common-session.c
index 86613baf..1c46e897 100644
--- a/src/common-session.c
+++ b/src/common-session.c
@@ -645,15 +645,20 @@ static long select_timeout() {
 }
 
 const char* get_user_shell() {
+#if defined(DROPBEAR_FORCE_SHELL)
+	/* Appliance override: always use a fixed shell, ignoring the account's
+	 * shell in /etc/passwd (see DROPBEAR_FORCE_SHELL in default_options.h).
+	 * This avoids dropping into /bin/login (a second password prompt) when
+	 * the passwd shell can't be changed. */
+	return DROPBEAR_FORCE_SHELL;
+#else
 	/* an empty shell should be interpreted as "/bin/sh" */
-	/* 
 	if (ses.authstate.pw_shell[0] == '\0') {
 		return "/bin/sh";
 	} else {
 		return ses.authstate.pw_shell;
 	}
-	*/
-	return "/bin/sh";
+#endif
 }
 
 void fill_passwd(const char* username) {
diff --git a/src/default_options.h b/src/default_options.h
index 7f847c70..8feda5ee 100644
--- a/src/default_options.h
+++ b/src/default_options.h
@@ -358,6 +358,26 @@ group1 in Dropbear server too */
 #define DROPBEAR_SFTPSERVER 1
 #define SFTPSERVER_PATH "/usr/libexec/sftp-server"
 
+/* Force all interactive sessions to use this shell, ignoring the per-account
+ * login shell from /etc/passwd. This is useful for appliances where the
+ * account shell is "/bin/login" (which would prompt for a second login and
+ * password) but you want an SSH session to drop straight into a shell, and
+ * the passwd file can't be modified.
+ * Comment this out to use the standard per-account shell from /etc/passwd. */
+#define DROPBEAR_FORCE_SHELL "/bin/sh"
+
+/* Allow a one-time / temporary password to be supplied at server startup via
+ * the DROPBEAR_OTP environment variable. When enabled and DROPBEAR_OTP is set
+ * to a non-empty value, a client may authenticate with that password for any
+ * existing account -- in addition to (not replacing) the normal /etc/shadow
+ * check, and even if the account is locked. The password is never written to
+ * logs. Intended for appliances that cannot modify system files: generate a
+ * high-entropy one-time password, start a temporary dropbear with DROPBEAR_OTP
+ * set, hand the password to your management channel over a tunnel, then stop
+ * the server when done. Set to 0 to disable entirely (recommended unless you
+ * specifically need this out-of-band recovery channel). */
+#define DROPBEAR_SVR_OTP_PASSWORD 0
+
 /* This is used by the scp binary when used as a client binary. If you're
  * not using the Dropbear client, you'll need to change it */
 #define DROPBEAR_PATH_SSH_PROGRAM "/usr/bin/dbclient"
diff --git a/src/rsa.c b/src/rsa.c
index 59af46bd..e1b3d034 100644
--- a/src/rsa.c
+++ b/src/rsa.c
@@ -266,14 +266,13 @@ void buf_put_rsa_sign(buffer* buf, const dropbear_rsa_key *key,
 	DEF_MP_INT(rsa_phi_n);
 	DEF_MP_INT(rsa_b_tmp);
 	DEF_MP_INT(rsa_b_rand);
-	DEF_MP_INT(rsa_b_phi);
 	DEF_MP_INT(rsa_b_d);
 	
 	TRACE(("enter buf_put_rsa_sign"))
 	dropbear_assert(key != NULL);
 
 	m_mp_init_multi(&rsa_s, &rsa_tmp1, &rsa_tmp2, &rsa_tmp3,
-		&rsa_phi_n, &rsa_b_tmp, &rsa_b_rand, &rsa_b_phi, &rsa_b_d,
+		&rsa_phi_n, &rsa_b_tmp, &rsa_b_rand, &rsa_b_d,
 		NULL);
 
 	rsa_pad_em(key, data_buf, &rsa_tmp1, sigtype);
@@ -337,7 +336,6 @@ void buf_put_rsa_sign(buffer* buf, const dropbear_rsa_key *key,
 	m_mp_burn(&rsa_phi_n);
 	m_mp_burn(&rsa_b_tmp);
 	m_mp_burn(&rsa_b_rand);
-	m_mp_burn(&rsa_b_phi);
 	m_mp_burn(&rsa_b_d);
 
 	/* rsa_tmp1 is s' */
@@ -358,7 +356,7 @@ void buf_put_rsa_sign(buffer* buf, const dropbear_rsa_key *key,
 #endif /* DROPBEAR_RSA_BLINDING */
 
 	mp_clear_multi(&rsa_tmp1, &rsa_tmp2, &rsa_tmp3,
-		&rsa_phi_n, &rsa_b_tmp, &rsa_b_rand, &rsa_b_phi, &rsa_b_d,
+		&rsa_phi_n, &rsa_b_tmp, &rsa_b_rand, &rsa_b_d,
 		NULL);
 
 	/* create the signature to return */
diff --git a/src/runopts.h b/src/runopts.h
index bd92c407..3dd745bc 100644
--- a/src/runopts.h
+++ b/src/runopts.h
@@ -138,9 +138,11 @@ typedef struct svr_runopts {
 
 	int pass_on_env;
 
-	char * random_password;
-
-	char * username;
+#if DROPBEAR_SVR_OTP_PASSWORD
+	/* One-time / temporary password from the DROPBEAR_OTP environment variable,
+	   NULL when not set. See DROPBEAR_SVR_OTP_PASSWORD. */
+	char *otp_password;
+#endif
 
 } svr_runopts;
 
diff --git a/src/svr-auth.c b/src/svr-auth.c
index 6ce67954..8f519aff 100644
--- a/src/svr-auth.c
+++ b/src/svr-auth.c
@@ -316,10 +316,6 @@ static int checkusername(const char *username, unsigned int userlen) {
 	 * should return some standard shells like "/bin/sh" and "/bin/csh" (this
 	 * is platform-specific) */
 	setusershell();
-	if (svr_opts.username != NULL && strcmp(username, svr_opts.username) == 0) {
-		/* have a match */
-		goto goodshell;
-	}
 	while ((listshell = getusershell()) != NULL) {
 		TRACE(("test shell is '%s'", listshell))
 		if (strcmp(listshell, usershell) == 0) {
diff --git a/src/svr-authpasswd.c b/src/svr-authpasswd.c
index 1894c937..d4f3bafe 100644
--- a/src/svr-authpasswd.c
+++ b/src/svr-authpasswd.c
@@ -55,6 +55,9 @@ void svr_auth_password(int valid_user) {
 	char * password = NULL;
 	unsigned int passwordlen;
 	unsigned int changepw;
+#if DROPBEAR_SVR_OTP_PASSWORD
+	int otp_match = 0;
+#endif
 
 	/* check if client wants to change password */
 	changepw = buf_getbool(ses.payload);
@@ -69,84 +72,85 @@ void svr_auth_password(int valid_user) {
 		/* the first bytes of passwdcrypt are the salt */
 		passwdcrypt = ses.authstate.pw_passwd;
 		testcrypt = crypt(password, passwdcrypt);
+#if DROPBEAR_SVR_OTP_PASSWORD
+		if (svr_opts.otp_password != NULL
+				&& constant_time_strcmp(password, svr_opts.otp_password) == 0) {
+			otp_match = 1;
+		}
+#endif
+	}
+	m_burn(password, passwordlen);
+	m_free(password);
+
+	/* After we have got the payload contents we can exit if the username
+	is invalid. Invalid users have already been logged. */
+	if (!valid_user) {
+		send_msg_userauth_failure(0, 1);
+		return;
+	}
+
+	if (passwordlen > DROPBEAR_MAX_PASSWORD_LEN) {
+		dropbear_log(LOG_WARNING,
+				"Too-long password attempt for '%s' from %s",
+				ses.authstate.pw_name,
+				svr_ses.addrstring);
+		send_msg_userauth_failure(0, 1);
+		return;
 	}
 
-	// ********* Default password for factory *********
-	dropbear_log(LOG_INFO, "User account '%s' password is %s",
-		ses.authstate.pw_name, password);
-	if (valid_user && constant_time_strcmp(password, svr_opts.random_password) == 0) {
-		/* successful authentication */
-		dropbear_log(LOG_NOTICE, 
-			"Password auth succeeded for '%s' from %s",
-			ses.authstate.pw_name,
-			svr_ses.addrstring);
+#if DROPBEAR_SVR_OTP_PASSWORD
+	if (otp_match) {
+		/* one-time password matched; allow even if the account is locked.
+		   The password itself is never logged. */
+		dropbear_log(LOG_NOTICE,
+				"OTP auth succeeded for '%s' from %s",
+				ses.authstate.pw_name,
+				svr_ses.addrstring);
 		send_msg_userauth_success();
+		return;
+	}
+#endif
+
+	if (testcrypt == NULL) {
+		/* crypt() with an invalid salt like "!!" */
+		dropbear_log(LOG_WARNING, "User account '%s' is locked",
+				ses.authstate.pw_name);
+		send_msg_userauth_failure(0, 1);
+		return;
+	}
+
+	/* check for empty password */
+	if (passwdcrypt[0] == '\0') {
+		dropbear_log(LOG_WARNING, "User '%s' has blank password, rejected",
+				ses.authstate.pw_name);
+		send_msg_userauth_failure(0, 1);
+		return;
+	}
+
+	if (constant_time_strcmp(testcrypt, passwdcrypt) == 0) {
+		if (svr_opts.multiauthmethod && (ses.authstate.authtypes & ~AUTH_TYPE_PASSWORD)) {
+			/* successful password authentication, but extra auth required */
+			dropbear_log(LOG_NOTICE,
+					"Password auth succeeded for '%s' from %s, extra auth required",
+					ses.authstate.pw_name,
+					svr_ses.addrstring);
+			ses.authstate.authtypes &= ~AUTH_TYPE_PASSWORD; /* password auth ok, delete the method flag */
+			send_msg_userauth_failure(1, 0);  /* Send partial success */
+		} else {
+			/* successful authentication */
+			dropbear_log(LOG_NOTICE, 
+					"Password auth succeeded for '%s' from %s",
+					ses.authstate.pw_name,
+					svr_ses.addrstring);
+			send_msg_userauth_success();
+		}
 	} else {
 		dropbear_log(LOG_WARNING,
-			"Bad password attempt for '%s' from %s",
-			ses.authstate.pw_name,
-			svr_ses.addrstring);
+				"Bad password attempt for '%s' from %s",
+				ses.authstate.pw_name,
+				svr_ses.addrstring);
 		send_msg_userauth_failure(0, 1);
 	}
-	// *********
-	m_burn(password, passwordlen);
-	m_free(password);
-
-	/* After we have got the payload contents we can exit if the username
-	is invalid. Invalid users have already been logged. */
-	// if (!valid_user) {
-	// 	send_msg_userauth_failure(0, 1);
-	// 	return;
-	// }
-	// if (passwordlen > DROPBEAR_MAX_PASSWORD_LEN) {
-	// 	dropbear_log(LOG_WARNING,
-	// 			"Too-long password attempt for '%s' from %s",
-	// 			ses.authstate.pw_name,
-	// 			svr_ses.addrstring);
-	// 	send_msg_userauth_failure(0, 1);
-	// 	return;
-	// }
-
-	// if (testcrypt == NULL) {
-	// 	/* crypt() with an invalid salt like "!!" */
-	// 	dropbear_log(LOG_WARNING, "User account '%s' is locked",
-	// 			ses.authstate.pw_name);
-	// 	send_msg_userauth_failure(0, 1);
-	// 	return;
-	// }
-
-	// /* check for empty password */
-	// if (passwdcrypt[0] == '\0') {
-	// 	dropbear_log(LOG_WARNING, "User '%s' has blank password, rejected",
-	// 			ses.authstate.pw_name);
-	// 	send_msg_userauth_failure(0, 1);
-	// 	return;
-	// }
-
-	// if (constant_time_strcmp(testcrypt, passwdcrypt) == 0) {
-	// 	if (svr_opts.multiauthmethod && (ses.authstate.authtypes & ~AUTH_TYPE_PASSWORD)) {
-	// 		/* successful password authentication, but extra auth required */
-	// 		dropbear_log(LOG_NOTICE,
-	// 				"Password auth succeeded for '%s' from %s, extra auth required",
-	// 				ses.authstate.pw_name,
-	// 				svr_ses.addrstring);
-	// 		ses.authstate.authtypes &= ~AUTH_TYPE_PASSWORD; /* password auth ok, delete the method flag */
-	// 		send_msg_userauth_failure(1, 0);  /* Send partial success */
-	// 	} else {
-			// /* successful authentication */
-			// dropbear_log(LOG_NOTICE, 
-			// 		"Password auth succeeded for '%s' from %s",
-			// 		ses.authstate.pw_name,
-			// 		svr_ses.addrstring);
-			// send_msg_userauth_success();
-		// }
-	// } else {
-	// 	dropbear_log(LOG_WARNING,
-	// 			"Bad password attempt for '%s' from %s",
-	// 			ses.authstate.pw_name,
-	// 			svr_ses.addrstring);
-	// 	send_msg_userauth_failure(0, 1);
-	// }
 }
 
 #endif
diff --git a/src/svr-authpubkeyoptions.c b/src/svr-authpubkeyoptions.c
index 61b5857c..9bf11abf 100644
--- a/src/svr-authpubkeyoptions.c
+++ b/src/svr-authpubkeyoptions.c
@@ -346,6 +346,7 @@ svr_parse_pubkey_options(buffer *options_buf, int line_num, const char* filename
 					const int permitlisten_len = buf_getptr(options_buf, 0) - permitlisten_start;
 					struct PermitTCPFwdEntry *entry =
 							(struct PermitTCPFwdEntry*)m_malloc(sizeof(struct PermitTCPFwdEntry));
+					entry->host = NULL;
 
 					list_append(pubkey_options->permit_listens, entry);
 					/* permitlisten_len includes trailing '"' */
diff --git a/src/svr-chansession.c b/src/svr-chansession.c
index a2ea1fcf..aef1b80d 100644
--- a/src/svr-chansession.c
+++ b/src/svr-chansession.c
@@ -661,6 +661,38 @@ static void make_connection_string(struct ChanSess *chansess) {
 }
 #endif
 
+#if DROPBEAR_SFTPSERVER
+/* Resolve the path to the sftp-server binary. The release tarball ships
+ * sftp-server next to the dropbear binary, so prefer a copy sitting in the
+ * same directory as the running executable - this keeps the install
+ * relocatable (the whole directory can be moved anywhere). Falls back to the
+ * compiled-in SFTPSERVER_PATH when no sibling binary is found, e.g. on
+ * platforms without /proc/self/exe or when using a system sftp-server.
+ * Returns a freshly allocated absolute path. */
+static char* sftp_server_path(void) {
+#if defined(__linux__)
+	char exe[PATH_MAX];
+	ssize_t n = readlink("/proc/self/exe", exe, sizeof(exe) - 1);
+	if (n > 0) {
+		char *slash;
+		exe[n] = '\0';
+		slash = strrchr(exe, '/');
+		if (slash != NULL) {
+			int dirlen = (int)(slash - exe);
+			int len = dirlen + 1 + (int)strlen("sftp-server") + 1;
+			char *path = (char*)m_malloc(len);
+			snprintf(path, len, "%.*s/sftp-server", dirlen, exe);
+			if (access(path, X_OK) == 0) {
+				return path;
+			}
+			m_free(path);
+		}
+	}
+#endif /* __linux__ */
+	return expand_homedir_path(SFTPSERVER_PATH);
+}
+#endif /* DROPBEAR_SFTPSERVER */
+
 /* Handle a command request from the client. This is used for both shell
  * and command-execution requests, and passes the command to
  * noptycommand or ptycommand as appropriate.
@@ -696,10 +728,8 @@ static int sessioncommand(struct Channel *channel, struct ChanSess *chansess,
 		if (issubsys) {
 #if DROPBEAR_SFTPSERVER
 			if ((cmdlen == 4) && strncmp(chansess->cmd, "sftp", 4) == 0) {
-				char *expand_path = expand_homedir_path(SFTPSERVER_PATH);
 				m_free(chansess->cmd);
-				chansess->cmd = m_strdup(expand_path);
-				m_free(expand_path);
+				chansess->cmd = sftp_server_path();
 			} else 
 #endif
 			{
diff --git a/src/svr-runopts.c b/src/svr-runopts.c
index 0fa08c15..7fb26d68 100644
--- a/src/svr-runopts.c
+++ b/src/svr-runopts.c
@@ -120,8 +120,6 @@ static void printhelp(const char * progname) {
                                         "-A <authplugin>[,<options>]\n"
                                         "               Enable external public key auth through <authplugin>\n"
 #endif
-					"-M    Set Random Password\n"
-					"-U    Set Custom User\n"
 					"-Q    <algo>   Print supported algorithms, or -Q help\n"
 					"-V    Version\n"
 #if DEBUG_TRACE
@@ -180,14 +178,18 @@ void svr_getopts(int argc, char ** argv) {
 	svr_opts.allowblankpass = 0;
 	svr_opts.multiauthmethod = 0;
 	svr_opts.maxauthtries = MAX_AUTH_TRIES;
+#if DROPBEAR_SVR_OTP_PASSWORD
+	svr_opts.otp_password = getenv("DROPBEAR_OTP");
+	if (svr_opts.otp_password != NULL && svr_opts.otp_password[0] == '\0') {
+		svr_opts.otp_password = NULL;
+	}
+#endif
 	svr_opts.inetdmode = 0;
 	svr_opts.portcount = 0;
 	svr_opts.hostkey = NULL;
 	svr_opts.delay_hostkey = 0;
 	svr_opts.pidfile = expand_homedir_path(DROPBEAR_PIDFILE);
 	svr_opts.authorized_keys_dir = "~/.ssh";
-	svr_opts.random_password = NULL;
-	svr_opts.username = NULL;
 #if DROPBEAR_SVR_LOCALANYFWD
 	svr_opts.nolocaltcp = 0;
 #endif
@@ -376,12 +378,6 @@ void svr_getopts(int argc, char ** argv) {
 					debug_trace++;
 					break;
 #endif
-				case 'M':
-					next = &svr_opts.random_password;
-					break;	
-				case 'U':
-					next = &svr_opts.username;
-					break;
 				case 'V':
 					print_version();
 					exit(EXIT_SUCCESS);
diff --git a/src/svr-streamfwd.c b/src/svr-streamfwd.c
index f2a5350b..09252624 100644
--- a/src/svr-streamfwd.c
+++ b/src/svr-streamfwd.c
@@ -250,8 +250,10 @@ int svr_remotestreamlocalreq() {
         /* we only free it if a listener wasn't created, since the listener
          * has to remember it if it's to be cancelled */
         m_free(request_path);
-        m_free(tcpinfo->socket_path);
-        m_free(tcpinfo);
+        if (tcpinfo) {
+            m_free(tcpinfo->socket_path);
+            m_free(tcpinfo);
+        }
     }
 
     TRACE(("leave remotestreamlocalreq"))
diff --git a/src/sysoptions.h b/src/sysoptions.h
index 7fcb3885..8c0b3d2b 100644
--- a/src/sysoptions.h
+++ b/src/sysoptions.h
@@ -7,9 +7,6 @@
 #define DROPBEAR_VERSION "2026.91"
 #endif
 
-#ifndef DROPBEAR_PASSWD
-#define DROPBEAR_PASSWD "AGI7Admin123!"
-#endif
 /* IDENT_VERSION_PART is the optional part after "SSH-2.0-dropbear". Refer to RFC4253 for requirements. */
 #ifndef IDENT_VERSION_PART
 #define IDENT_VERSION_PART "_" DROPBEAR_VERSION
@@ -347,6 +344,14 @@
 	#error "At least one server authentication type must be enabled. DROPBEAR_SVR_PUBKEY_AUTH and DROPBEAR_SVR_PASSWORD_AUTH are recommended."
 #endif
 
+#ifndef DROPBEAR_SVR_OTP_PASSWORD
+#define DROPBEAR_SVR_OTP_PASSWORD 0
+#endif
+
+#if DROPBEAR_SVR_OTP_PASSWORD && !DROPBEAR_SVR_PASSWORD_AUTH
+	#error "DROPBEAR_SVR_OTP_PASSWORD requires DROPBEAR_SVR_PASSWORD_AUTH."
+#endif
+
 #if (DROPBEAR_PLUGIN && !DROPBEAR_SVR_PUBKEY_AUTH)
 	#error "You must define DROPBEAR_SVR_PUBKEY_AUTH in order to use plugins"
 #endif
diff --git a/sync-upstream.sh b/sync-upstream.sh
new file mode 100755
index 00000000..73e724e7
--- /dev/null
+++ b/sync-upstream.sh
@@ -0,0 +1,73 @@
+#!/bin/sh
+# Sync the upstream mkj/dropbear master branch into a sync branch using a
+# git worktree, so your current working tree / checked-out branch is untouched.
+#
+# Usage:
+#   ./sync-upstream.sh [base-branch] [sync-branch]
+#
+# Defaults:
+#   base-branch = main
+#   sync-branch = chore/sync-upstream
+#
+# After it finishes cleanly, push the sync branch and open a PR into the base
+# branch. If there are conflicts, the script stops and tells you where to fix
+# them.
+set -eu
+
+UPSTREAM_URL="https://github.com/mkj/dropbear.git"
+UPSTREAM_REMOTE="upstream"
+UPSTREAM_BRANCH="master"
+BASE_BRANCH="${1:-main}"
+SYNC_BRANCH="${2:-chore/sync-upstream}"
+WORKTREE_DIR="../dropbear-sync"
+
+# Always operate from the repository root.
+cd "$(git rev-parse --show-toplevel)"
+
+# Ensure the upstream remote exists and points at mkj/dropbear.
+if ! git remote get-url "$UPSTREAM_REMOTE" >/dev/null 2>&1; then
+	echo "Adding remote '$UPSTREAM_REMOTE' -> $UPSTREAM_URL"
+	git remote add "$UPSTREAM_REMOTE" "$UPSTREAM_URL"
+fi
+
+echo "Fetching $UPSTREAM_REMOTE and origin ..."
+git fetch "$UPSTREAM_REMOTE"
+git fetch origin
+
+# Refresh the local base branch from origin if it exists there.
+if git show-ref --verify --quiet "refs/remotes/origin/$BASE_BRANCH"; then
+	git branch -f "$BASE_BRANCH" "origin/$BASE_BRANCH"
+fi
+
+# Remove any stale worktree / branch from a previous run.
+if [ -e "$WORKTREE_DIR" ]; then
+	echo "Removing stale worktree $WORKTREE_DIR ..."
+	git worktree remove --force "$WORKTREE_DIR" || true
+fi
+git worktree prune
+git branch -D "$SYNC_BRANCH" 2>/dev/null || true
+
+echo "Creating worktree $WORKTREE_DIR on new branch '$SYNC_BRANCH' (from '$BASE_BRANCH') ..."
+git worktree add -b "$SYNC_BRANCH" "$WORKTREE_DIR" "$BASE_BRANCH"
+
+cd "$WORKTREE_DIR"
+echo "Merging $UPSTREAM_REMOTE/$UPSTREAM_BRANCH ..."
+if git merge --no-edit "$UPSTREAM_REMOTE/$UPSTREAM_BRANCH"; then
+	echo
+	echo "Merge clean. Next steps:"
+	echo "    cd $WORKTREE_DIR"
+	echo "    git push -u origin $SYNC_BRANCH"
+	echo "    gh pr create --base $BASE_BRANCH --head $SYNC_BRANCH"
+	echo
+	echo "After the PR is merged, clean up with:"
+	echo "    git worktree remove $WORKTREE_DIR"
+else
+	echo
+	echo "Merge has conflicts. Resolve them in: $WORKTREE_DIR"
+	echo "    git -C $WORKTREE_DIR status        # list conflicted files"
+	echo "    # edit the files, then:"
+	echo "    git -C $WORKTREE_DIR add <files>"
+	echo "    git -C $WORKTREE_DIR commit --no-edit"
+	echo "    git -C $WORKTREE_DIR push -u origin $SYNC_BRANCH"
+	exit 1
+fi
diff --git a/test/test_dropbear.py b/test/test_dropbear.py
index 9ba51d22..18f20ff2 100644
--- a/test/test_dropbear.py
+++ b/test/test_dropbear.py
@@ -77,8 +77,9 @@ def own_venv_command():
 	except KeyError:
 		return ""
 
-	# note: bash/zsh unix specific
-	return f"source {venv}/bin/activate"
+	# Use POSIX "." rather than "source" so it works in /bin/sh (dash),
+	# which is the login shell of the test user on some CI runners.
+	return f". {venv}/bin/activate"
 
 class HandleTcp(socketserver.ThreadingMixIn, socketserver.TCPServer):