AFAICT, U-Boot relies on the "Legacy BIOS bootable" attribute to decide
whether a GPT partition should be among the partitions it searches
for bootflows.
AFAICT it's being deprecated in many tools: e.g. under Debian, neither
`gdisk -l` nor `fdisk -l` display that information, I can't find any way
to set/undet that flag in `fdisk` and in `gdisk` it is hidden under
"extra functionality (experts only)".
AFAICT there is currently only one non-deprecated alternative, which is
to use the PARTITION_SYSTEM_GUID (C12A7328-F81F-11D2-BA4B-00A0C93EC93B)
for that partition's GUID. But IIUC that GUID is meant for the EFI
partition, which would be a weird choice for partitions that hold
GNU/Linux ext4 rootfs.
Is there any hope to see some other option (not sure what that would be)?
Stefan
