Random SCSI lockup during start NetBSD 6.0

[Dennis Boon <dboon%casema.nl@localhost>]

Hello,

Sorry to bother you guys again, this time maybe with something not related to 
NetBSD:

During the startup of NetBSD on my A3000 I get a random lockup on the SCSI bus 
right after the following (I left out the bits between the <> brackets:

ahsc0: target now synchronous, period=224ns, offset=12
sd0 at scsibus0 target 0 lun 0: <my HD description>
sd0: <drive geometry>

Then it hangs sometimes, with the HD light staying on. At the moment, the HD is 
the only SCSI device on the chain. The HD is connected through a 68 pins 
connector on the HD to the 68 pins cable to the 68 to 50 pins adapter to the 50 
pins connector on the mainboard on one side. The other side on the cable is 
actively terminated with a 68 pins terminator.

Drive has TRGT INIT and UNIT ATTN disabled (latter also tried enabled). SCAM is 
disabled.

It drives me nuts that it is a random thing.... It seems to improve my chances 
to get through this point if I disable all AmigaDOS partitions (4 of them), but 
that is maybe wishful thinking.

The SCSI chip has been upgraded to an AMD one. NVRAM on the A3000 is now set to 
support multiple LUNs and synchronous transfer.

Any ideas?