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Heresyte

Member

Registered: 2008-07-10

Posts: 19

[SOLVED] New motherboard only boots with fallback kernel

I replaced my motherboard and when the new one boots I get an error similar to this one (I just copied this from another thread):

:Loading root filesystem module...
Attempting to create root device '/dev/sdb1'
Waiting for devices to settle... done.
ERROR: Failed to parse block device name for '/dev/sdb1'
unknown
ERROR: root fs cannot be detected. Try using the rootfstype= kernel parameter.

Root device '/dev/sdb1' doesn't exist, attempting to create it.
ERROR: Failed to parse block device name for '/dev/sdb1'
ERROR: Unable to create/detect root device '/dev/sdb1'

Dropping to a recovery shell... type 'exit to reboot
NOTE:klibc contains no 'lc' binary, use 'echo *' instead

If the device '/dev/sdb1' gets created while you are here, try adding 'rootdelay=8' or higher to the kernel command-line

ramfs$

The kernel never says that it detected any drives (and none are present in /dev).  Trying to boot from old livecds gives the same problem.

If I switch to using the fallback kernel the drives are detected and it boots fine.  What exactly is the fallback kernel, and what problem would cause that to work but not the regular one?

Last edited by Heresyte (2008-12-11 03:14:00)

kjon

Member

From: Temuco, Chile

Registered: 2008-04-16

Posts: 398

Re: [SOLVED] New motherboard only boots with fallback kernel

boot your fallback image,
at root prompt regenerate your initcpio image with:

mkinitcpio -p kernel26

reboot and problem solved.

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They say that if you play a Win cd backward you hear satanic messages. That's nothing! 'cause if you play it forwards, it installs windows.

iBertus

Member

From: Greenville, NC

Registered: 2004-11-04

Posts: 2,228

Re: [SOLVED] New motherboard only boots with fallback kernel

To be more specific, it's not a fallback kernel, but rather a fallback ramdisk image. The standard ramdisk image is built to only have the modules needed by your hardware while the fallback image includes pretty much everything. As kjon said, rebuilding the standard image should autodetect modules and fix the issue.

Heresyte

Member

Registered: 2008-07-10

Posts: 19

Re: [SOLVED] New motherboard only boots with fallback kernel

Awesome awesome, that worked thanks.

I got this same problem trying to boot to a couple different livecds, which makes me think it must be a recent module that I need.  Is there some way I can pinpoint what module was causing the problem?

bangkok_manouel

Member

From: indicates a starting point

Registered: 2005-02-07

Posts: 1,556

Re: [SOLVED] New motherboard only boots with fallback kernel

i guess you'll have to add the needed module to your /etc/mkinitcpio.conf, otherwise you'll most likely get the same issue when the next kernel update will arrive. In addition, you've built your image with all modules, which is, well, harmless but maybe not the lightest option.

toad

Member

From: if only I knew

Registered: 2008-12-22

Posts: 1,775

Website

Re: [SOLVED] New motherboard only boots with fallback kernel

At the risk of being hanged, drawn and quartered, for resurrecting an old thread I wish to state the obvious for the uninitiated - you (as indeed I and everybody else) will have to remount the drive to be writeable.

I stumbled over it and so may somebody else...

There is a special warning telling you how to, but nevertheless here it is again:

mount -n -o remount,rw /dev/sdxX /

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never trust a toad...
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