Raspberry Pi Zero 2 W with Ubuntu

To setup the Pi to act as a host, made sure you have these:

Pi: Purchase it via raspberrypi.com.
Case: A case is not required, but it is recommended. Some cases come with heat sink to help keep your Pi a little cooler.
Power supply: A micro USB power supply with at least 2.5A at 5v of power. Some cell phone chargers are compatible. You may have one already.
SD Card: You need a 32GB or larger micro SD card. MMS messages need a place to store the media file. More messages, more storage needed. Recommend a Kingston or SanDIsk. You may already have one.
Adapter: Make sure your desktop/laptop computer has a SD card reader/writer. If not, you can purchase a USB to Micro SD adapter for about $10.
Download and Install: The Raspberry Pi Imager software. It will write the Ubuntu server software to the SD card. Get it from from raspberrypi.com/software.

Follow these steps to install Ubuntu:

Insert the SD card into your laptop/desktop reader or adapter.
Open the Raspberry Pi Imager application.
Select your device as the Raspberry Pi Zero 2 W.
Select the OS, under "Other General-purpose OS", select the Ubuntu Server for ARM64 and latest LTS version.
Select the storage device as the SD card you inserted in step 1.
Select Customization and enter the following:
1. A host name, i.e. "raspi02w"
2. Localization for timezone and keyboard type (despite no keyboard!)
3. User name and password for logon
4. Enter Wifi SSID and password. It needs to be a for a 2.4GHz network. If unsure, logon to your router to confirm. Look for the wireless or Wifi settings section.
5. Enable SSH and use password authentication.
Write the image to the SD card
Once done, remove the SD card from laptop/desktop and insert into the Raspberry Pi.
Power on the Raspberry Pi.
Logon to your local router and check for current IP addresses. It may be under DHCP or current clients or other.
Look for the "raspi02w" name and note the IP address.
Open your favorite SSH client and connect to the raspi02w IP address.
Logon using the ID and password set in step 6.3.
Need some updates:
```
sudo apt update && sudo apt upgrade
```
Need some power management software:
```
sudo apt install iw
```
To disable power management, type this command:
```
sudo iw wlan0 set power_save off
```
We'll schedule power save off at each reboot:
```
sudo crontab -e
```

If asked about editor, select "nano". Paste the following at the bottom:

@reboot /usr/sbin/iw wlan0 set power_save off > /tmp/power_save_log.txt 2>&1

Setup swap space using these commands:

sudo fallocate -l 256M /swap.img
sudo chmod 600 /swap.img
sudo mkswap /swap.img
sudo swapon /swap.img

To re-enable after next reboot:
```
sudo nano /etc/fstab
```
Paste the following at the bottom of the file:
```
/swap.img swap swap defaults 0 0
```
Save and exit
Adjust the Swappiness value lower so as to not use the swap file unless needed. Ubuntu default is 60. We'll set it to 30:
```
sudo sysctl vm.swappiness=30
```
To make sure it remembers after reboot, open sysctl.conf:
```
sudo nano /etc/sysctl.conf
```
Paste this line at the bottom:
```
vm.swappiness=30
```
Save and exit
Reboot and confirm everything is set:
```
sudo shutdown --reboot now
```
After a minute or two, reconnect via SSH and logon.

Type these commands to confirm settings:

iw wlan0 get power_save
free -h
cat /proc/sys/vm/swappiness

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