Ultra1 does not boot after kernel upgrade to 2.6.26

["Donatas Ciuksys" <donatas.ciuksys@mif.vu.lt>]

Hi,

I was running etch on my Ultra1 happily for last 22 months, and tried to upgrade to lenny recently. Package upgrades were successful, but kernel upgrade gave me unbootable system.
Messages on the screen:

-------------------------------------
...
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
Loading, please wait...
Begin: Loading essential drivers... done
Begin: Running /scripts/init-premount... done.
Begin: Mounting root file system... Begin: Running /scripts/local-top... done.
Begin: Waiting for root file system...

-------------------------------------

Here system stops, after some time I get a message:

ALERT! /dev/sda1 does not exist. Dropping to a shell!

and I get busybox shell.

Any suggestions?

Regards,
Donatas