Nothing much to report yet...
I've read the Bluetooth chip's manual now. It's a complicated part, a computer in itself. Those two 115,200 baud serial COM lines on the unpopulated connector (CN8) I had discovered a few weeks ago are most probably the Rx and Tx lines going to/from the main CPU to this chip. So that's probably a Bluetooth diag. port.
Both the working board and broken board talk the same way to each other initially, well after the USB has finished initialising. No messages differ at this point. The working board however does a 2nd reset after about 8 seconds and tells the chip to start reporting back what Bluetooth devices are "around".
The broken board never gets to the 2nd reset.
The working board sends a single signal to the video-input/iThing chips (on the two wire bus) about 0.5 secs after the initial Bluetooth comms, but that never happens on the broken board. However that is the 2nd time it happens (the first happens on both boards much earlier - even before the USB chip is started). So I'm pretty sure that area of the board I had stuffed around with hasn't been changed for the worse.
So I think the Bluetooth chip is working. Something else within that 0.5 second period is not working, but I'm yet to discover what signal that is. The touch screen happens a little bit after, the audio chip happens a little bit before... What else is there?!
