Just tried a brand new null-modem cable with exactly the symptoms. To confirm, I'm connecting directly to the player - not through a dock. And I have checked my HyperTerminal settings, include flow control.

I also tried typing 'player', after typing 'Q' into HyperTerminal, which does, as expected, relaunch the player software. This confirms absolutely that the empeg is receiving the commands I send it, but doesn't explain why nothing is getting back to the PC.

Another interesting symptom - when attempting the upgrade, if the player is unplugged from the mains at the point when it says 'apply power now', the player does not boot when power is applied. The white LED pulses, but nothing else occurs. I need to cancel the upgrade wizard, unplug the empeg again, and plug it back in, before it'll then boot up.