Cannot open root device "<NULL>"..please append a correct "root=" boot option...

Mauricio Henriquez mhenriquezs at
Thu May 28 11:03:28 PDT 2009

Hi guys,

I just finish my third LFS system this time using LFS 6.4 usual I 
make all the process in a vmware machine becouse I use it for teching 
porpuses, but now at the end I have a kernel panic due to the fact that 
it can't mount the root filesystem, the error is the one at subject:

Cannot open root device "<NULL>"..please append a correct "root=" boot are all the available partitions:
[2.871] 0b00 1048575 sr0 driver: sr
<Kernel panic stuff here>

It seems that is only able to see the "sr" device with the "sr0" 
partition witch seems to be the cdrom right?

I'm at chapter 9 (kind of) becouse due to the use of a virtual disk of 
course I don't install grub directly from my host PC, intead I boot the 
vmware machine with a supergrubdisk and try to boot first manually and 
then store the grub config in the virtualdisk from grub console (this 
technique works ok for me when I use lfs 6.1 and 6.2)...

To format the virtualdisk at the beggining I boot the vmware machine 
with a gparted iso and do the format, the debugfs for that partition 
give me this:
debugfs 1.41.3 (12-Oct-2008)
Filesystem features: has_journal resize_inode dir_index filetype 
needs_recovery sparse_super large_file

can be that the problem? (those are the "can be" options acording to the 
book), or do I need to pass a "...root=sr0" boot option to the 
kernel?(witch seems to be the cdrom right?), any other sugestion or 
place to look at?

Any help would be apreciated...



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