USB controller not found/working on Sun V40z workstation

Problem stated in the subject. I need USB to work badly, as there is
no PS/2 for keyboard and mouse in this workstation.

I've tried 5.4 STABLE, 6.0 CURRENT and 6.0 BETA. Out of 30 boots USB
was detected twice and keyboard was working too. I attach log from two
of those successful boots (5.3 RELEASE and 6.0 CURRENT) and a late one
from 6.0 BETA boot -v. Kernel config is attached too.

Any help and suggestions appreciated!

Thanks, /S