It would appear that the grub @setup@ built-in command has been broken since LBA48 support was added in 6593. Consider the following grub script: <pre> device (hd0) /dev/rlofi/4 root (hd0,0) setup (hd0) quit </pre> This currently fails with an unhelpful error message: <pre> # /ws/xplat/proto/boot/grub/bin/grub --batch ... grub> device (hd0) /dev/rlofi/4 grub> root (hd0,0) Filesystem type is fat, partition type 0xc grub> setup (hd0) Checking if "/boot/grub/stage1" exists... yes Checking if "/boot/grub/stage2" exists... yes Checking if "/boot/grub/fat_stage1_5" exists... yes Running "embed /boot/grub/fat_stage1_5 (hd0)"... 18 sectors are embedded. succeeded Running "install /boot/grub/stage1 (hd0) (hd0)1+0 p (hd0,0)/boot/grub/stage2 /boot/grub/menu.lst"... failed Error 1: Filename must be either an absolute pathname or blocklist grub> quit </pre> After digging for a while, it became apparent that one of the arguments to the @install@ built-in is os a block list; i.e., @(hd0)1+0@. This block list should list the start and end sector of the embedded @fat_stage_1_5@, but here it is clearly not correct. The addition of LBA48 support did not completely account for all of the integer type changes, and there are a few more places that need different @printf@ format strings. Once fixed, the install process functions correctly: <pre> ... Running "embed /boot/grub/fat_stage1_5 (hd0)"... 18 sectors are embedded. succeeded Running "install /boot/grub/stage1 (hd0) (hd0)1+18 p (hd0,0)/boot/grub/stage2 /boot/grub/menu.lst"... succeeded Done. grub> quit </pre> Note, in particular, the block list now includes sectors 1 through 18.