I had a PL-2303 usb to serial on the hybrid/core which was working fine before the update. After the update it stopped working, and started withe pnp loop. The adapter never asked to be added before, so that was strange, but the only way to stop it was to ignore it always, so I disconnected it.
I thought maybe it had gone bad, so I found that the MB on the core/hybrid had a serial header, I bought the stuff to be able to connect to that serial port directly on the mb which the system sees as /dev/ttyS0, but still the receiver would not detect with the pnp script, and when manually adding the device template for it, it would disable and not register it.
If I hookup the hybrid/core with a null modem cable to my laptop with a com port, using hyperterm on the windows side (laptop) and minicom on the hybrid/core, if I start typing I see echos of some data on the opposite machine, the characters are funky, but it looks like there's communication. At this point i think my port and cable are fine, but something in system no longer wants to work.