Failure to boot

Tobias Gasser lfs at
Wed Aug 13 15:46:34 PDT 2008

> Root-FFS: No NFS server available, giving up
> VFS: Unable to mount root fs via NFS, trying floppy
> VFS: Cannot open root device "sda4" or unknown-block(2,0)
> Please append a correct "root=" boot option; here are the available 
> partitions
> 0300 156290904 hda driver: ide-disk
> 0301 102398278 hda1
> 0302   29294527 hda2
> 0303       979965 hda3
> 0304   23615550 hda4
> 1600     4194302 hdc driver: ide-cdrom
> Kernel panic -not syncing: VFS: Unable to mount root fs on 
> unknown-block(2,0)

you get a listing of available partitions on HDA, found by the ide-disk 

> For the sake of completeness, my grub entry is:
> title LFS 6.3
> root (hd0,3)
> kernel /boot/lfskernel- root=/dev/sda4

as your log shows partitions found on HDA not SDA you probably have to 
change your grub menu to "... root=/dev/hda4"

> I just double checked with gparted to make sure lfs is indeed on sda4, 
> and it is.  I also checked my kernel configuration and I did indeed 
> rebuild it with the proper modules.  I also double checked the 
> timestamps of the bzImage in the source tree and the kernel image in 
> /boot to make sure that I didn't forget to copy it after it was 
> compiled.  I'm clearly overlooking something, but I'm not sure what.

the partitions found by ubuntu on SDAx will be found from your actual 
lfs-kernel according to the log on HDAx.

you probably have still some old PATA drivers active. this driver seems 
to feel responsible for your disk on /dev/hda, and thus no driver is 
responsible for the same disk on /dev/sda.

* second try:

you copied the kernel to /dev/sda4/boot (on the LFS-partition) or 
/dev/sda2/boot (ubuntu)?

copy it to both and play arround with

  root (hd0,X)
  kernel (hd0,Y)/boot/...

where X/Y means all possible permutations with 1 and 3. (eventually try 
again with root=/dev/sda4 instead of hda4)


More information about the lfs-support mailing list