The eMMC is now the boot/root device and the SD card is a manual
failsafe. U-Boot has no persistent env and always prefers an SD with a
boot.scr, so the SD's boot script is kept dormant as
boot-failesafe-rename-to:boot.scr.
- Locate the SD by root UUID instead of /dev/mmcblk0p2
- Preserve the SD's dormant boot script; never create a live boot.scr
and refresh the dormant copy from the eMMC
- Copy fstab and armbianEnv.txt with the root UUID rewritten to the SD's
- Add rsync -x; drop the Pi-specific /boot/firmware exclude
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>