preupgrade grub2 failed: now can't boot

[Greg Woods]

On Mon, 2012-02-06 at 19:48 -0500, sean darcy wrote:

> grub2-install --no-floppy /dev/sdg
> /sbin/grub2-setup: warn: Your embedding area is unusually small. 
> core.img won't fit in it..
> /sbin/grub2-setup: warn: Embedding is not possible.  GRUB can only be 
> installed in this setup by using blocklists.  However, blocklists are 
> UNRELIABLE and their use is discouraged..
> /sbin/grub2-setup: error: will not proceed with blocklists.
> 
> What do I do now! Embedding area???

This is the area at the beginning of the disk, before the first
partition. Grub2 needs the first partition to start at 2048, but default
partition layouts from Grub-1 systems start at 63. I have run into this
several times and it is a royal pain. There may be some games you can
play with gparted (shrink the partition, then move it), or you can do
like I did, which is to dump the first partition, change it to start at
2048 (shrinking it a bit), making a new file system on the new
partition, and restoring it.

--Greg