Re: Unable to boot into CompactFlash card - card not found by initrd

[Michael Lange <klappnase@freenet.de>]

Hi,

Thus spoketh Brian <ad44@cityscape.co.uk> 
unto us on Thu, 19 Jan 2012 18:25:35 +0000:

(...)
> 
> The UUID on the 'search' line should be that of the partition on the CF
> card which holds the kernel and the initrd. The line can omitted, as can
> the 'set root' line. The 'linux' and 'initrd' lines are required.

No, there is a spearate /boot partition on the internal HDD
(on /dev/sda1), the CF card cannot be booted directly,  because the BIOS
doesn't know about it.

> 
>    /vmlinuz-2.6.32-5-686 root=LABEL=CFCARD ro
> 
> tells GRUB it will find a file vmlinuz-2.6.32-5-686 on the card in the
> root of a partition which has the label 'CFCARD'. Is such a file there?
> And has the partition been labelled ('tune2fs -L' is one method)?

I think that it rather shows grub where to look for the kernel: in the
root of the file system given by the "search" or the "set root" line, and
that it then tells the kernel to mount a file system named "CFCARD" as / .

There are no problems with the first part, the kernel boots but then
fails to find the root file system because the device files have not been
created.
I am quite sure now that this is caused by the way removable
devices are handled at boot time. By staring a couple of times at the
rushing-by boot messages that I get when I boot into the working system I
have installed on /dev/sda2, I found that the CF card is recognized just
*after* the root file system is mounted; the next thing after mounting /
is that udev starts, then I see the message "Synthesizing initial hotplug
events..." (or so) and immediately after this the CF card appears.

So I think what i would need is a way to start at least one of these
hotplug events, the one that installs the CF card, from within the
initrd, *before* it tries to mount / from a device which has not yet been
initialized.

Regards

Michael


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