I've finally managed to catch the oops on the Ultras :) through the serial
console.

I've been having problems forever with Ultra AXi PCI and Linux, hanging
from time to time: more activity more hangs.

It used to be a SIR Reset, but this one has disappeared -as David said ;)- 
in this version. There are still errors to be corrected, so I hope my
ksymoops are useful. If you need more information just tell me.

I attach the log.

Thanks
Pau