My weird first experience with batocera 5.27:
2) The system boots fine. (This time)
3) The file system is automatically expanded.
4) Batocera launches.
6) Get stuck at BIOS screen where the system would normally list all of the connected drives. Disconnecting the usb drive allows the system to proceed. I attempted this with multiple USB media and had the same results.
It appears that this is related to the file expansion operation. This BIOS lockup behavior is reproducible with two entirely separate core 2 systems: A dual core E8500 (motherboard Gigabyte GA-EP45-UD3R) and a quad core Q6600 (motherboard Gigabyte GA-P35-DS3L). A third i3 system boots just fine with the exact same expanded file system plugged in, so this appears to affect some systems and not others.
I have disabled auto-expansion in batocera-boot.conf prior to the first boot, and my system now survives reboots just fine. I think this workaround will work for me since I use network storage anyway. I wanted to put this here for any owners of similar systems that were as perplexed as I was, as well as bring it to the attention of the developers.
I’m very much looking forward to trying out 5.27. Thanks for everyone who has worked on this!