Good news, everyone! (because you were all waiting with bated breath, right )

It seems that the boot loop was caused by an issue with the proximity sensor. Just by not attaching it the phone boots and runs just fine. I miss the standby screen and all, and doubletap to wake doesn't work... But it's a small price to pay (and proxy sensors are cheap!)

Maybe someday this will help a poor, clumsy soul like me.