Sun Fire V240 does not boot anymore...

Hi all,

after applying recommended patchset (Feb. 23rd) our V240 no longer is booting.
It is stuck in a
reset-loop and on the console we can see the following messages:

Probing system devices
Probing memory
Probing I/O buses

Sun Fire V240, No Keyboard
Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
OpenBoot 4.18.10, 2048 MB memory installed, Serial #72705073.
Ethernet address 0:14:4f:55:64:31, Host ID: 84556431.


Rebooting with command: boot
Boot device: /pci@1c,600000/scsi@2/disk@1,0:a  File and args:
not found: randtick
not found: randtick
not found: randtick
not found: randtick
not found: randtick
not found: randtick
krtld: error during initial load/link phase

SC Alert: Host system has shut down.

SC Alert: Host System has Reset

Executing Power On Self Test
.....

any idea what's going on here??

thanks a lot,
christian