Comment # 3 on bug 865227 from Michael Chang

Hi Diego,

Sorry for reply you after a long time.

As you have noticed, it worked for raw partitions, but failed with lvm. It's
because grub2 writes on-the-fly to the raw sectors on one device without
touching any other metadata. That means lvm feature likes multiple device (RAID
.etc) and checksum would break after such operations.

If you have to use lvm and also wanting grub2-reboot to work, you need to
partition a separate boot partition without lvm and with file system like
ext2/3/4 that raw sectors can be written directly without breaking it's
meta-data integrity.

Therefore I close this as wonfix because that's something not implemented and
not supported.