[cobalt-developers] Qube2: booting different kernel?

[Brian Warner <warner@xxxxxxxxxx>]

Howdy all..

I've been looking into building up a debian install on a Qube2 that I recently
inherited. My first step was to replace the hard drive with a larger one
(insuring that I could always go back to the original drive, since I know it
works). But I've been unable to get the new drive to boot.

I partitioned the new drive roughly the same as the original, and I copied the
entire contents of the old drive to the new one (by mounting both drives on my
x86 linux box, and using tar). However, watching the Qube2 attempt to boot the
same old kernel from the new drive (via the serial port) showed only errors:

 56:warner@aleph% cu --baud 115200 --line /dev/ttyS0
 Connected.
 Cobalt Microserver Diagnostics - 'We serve it, you surf it'
 Built Tue Dec 15 04:11:42 PST 1998
 .. 
 Cobalt: bfd
 Decompressing  done
 Jump_to_Real_Kernel: disk error, trying BFD again
 Decompressing  done
 Jump_to_Real_Kernel: disk error, trying BFD again
 get_root_dev: nr_boot_failures 0x00000002 exceeds maxtries 0x00000002 for boot_index 0x00000000

So my question to the experts is: how does the Qube2 boot? Is there a block
table (ala 'lilo') that has to match the physical placement of the kernel?
Does the prom know how to parse an ext2 filesystem and thus search for
/boot/vmlinux.gz (or /usr/games/.doug, I've heard rumored, if you press a
magic set of buttons and stand on one foot..). Is there a restriction on the
partition size or location of the kernel? Is there any way to get the Qube2
prom to boot from a particular file? (I've heard that more recent proms are
more flexible about this).

I'm guessing that there is a two-stage loader involved (given the two
"Decompressing done" messages that appear when it boots successfully), and
that the first is probably in ROM, and probably mounts /dev/hda1 and looks for
/boot/vmlinux.gz . (and in fact the "bfd" command appears to take a filename,
because if I boot the original disk with anything other than "bfd" or "bfd
/boot/vmlinux.gz" it fails). But are there restrictions as to how that drive
must be partitioned, or sized? Any idea what I'm missing?


Any information is greatly appreciated..

 -Brian
   warner@xxxxxxxxxx