I have recently finished building linux from scratch. However, the system couldn't boot. I used Ubuntu 9.04 (32 bit) as host and lfsbook version 6.4. I use the GRUB that shipped with Ubuntu. And I didn't do the chapter 8.4.
During the boor process, I got this message:
Root-NFS: No NFS server available, giving up.
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "hda4" or unknown-block(2,0)
Please append a correct "root=" boot option;here are the available partitions:
0b00 104857 sr 0 driver: sr
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)