Mac Mini Late 2014 and SD card.
...
starting version 239
Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/live-top ... done.
Begin: Running /scripts/live-premount ... done.
BOOT Failed
...
...
live-boot will now start a shell. The error message was:
Unable to find a medium containing a live file system
BusyBox ...
Enter 'help' ...
(initramfs) _
Mac Mini Late 2014 and SD card.
I found this error message by
grephere https://github.com/grml/live-boot-grml/blob/master/components/9990-main.sh#L87 and have no idea how to debug/fix/workaround.