Comment 21 for bug 1097570

@Colin,

 I del the grub.cfg in recovery partition, after that it will enter grub shell.
 from the result, I thought the $prefix is zero or not exist.

grub> cat (memdisk)/grub.cfg

if [ -z "$prefix" -o ! -e "$prefix" ]; then
        if ! search --file --set=root /.disk/info; then
                search --file --set=root /.disk/mini-info
        fi
        set prefix=($root)/boot/grub
fi
if [ -e $prefix/$platform/grub.cfg ]; then
        source $prefix/$platform/grub.cfg
else
        source $prefix/grub.cfg
fi