And a small remark about your x86 without serial port. Two systems connected via usb-serial+null-model-cable+usb-serial work quite well for this type of tests. Add "console=tty0 console=ttyUSB0,115200,n8" to the bootargs of your test system and boot it up. The system used for gathering the kernel output just has to run "screen /dev/ttyUSB0 115200" and dump all the data.
Hi Sven
The box does have a couple of FTDI chips. But i've had mixed results with such a setup. Often the Opps does not get out of the USB subsystem before the box is dead. I can give it a try and see what happens in this case.
Andrew