Here's what I would do in your situation:

#1: Upgrade to v2.00b7 (or b3, but b7 is much better). This upgrade is needed for step #2 below.

#2: Install the Hijack kernel -- it has some useful features for debugging, as you will see.

#3: Fix your front panel buttons, by adding these lines to config.ini (not a 100% fix, but almost):

[Startup]

ReserveCache=12

#4: Now that everything is in place, plug the unit in at home, on the AC supply, and hook up the serial port to a terminal emulator so we can see what is happening.

#5: To reproduce in-car behaviour while on AC power, press and hold the KNOB (or MENU on the remote) until the Hijack menu appears. Go to the "Force AC/DC Power Mode" item, and use the knob to change the setting to "Force DC/Car", and then reboot when prompted.

If both drives work, then pull the power plug, wait a few seconds, and plug it back in again. If they still work, well that tells us it is power related. If they don't work, then.. time to look at the serial output and perhaps post it HERE for us to look at.

Cheers