[jornada] Possible dead J720 (with HP flash hack)

Folks,

I may have killed my Jornada, but I'm not quite sure why.

Some background: I was attempting to upgrade my kernel on my 720 (which has
the flash ROM hack by John Ankcorn; thanks John!) but booting it didn't work,
so I expected to be able to revert to the old kernel at the boot> prompt. I
hooked
up the serial port on my desktop to the Jornada and typed away. But, while
some
weeks ago the keyboard responded to my keypresses, it now no longer does so!
This means that I effectively have a brick -- is there any way to get out
of this
situation?

I've included the boot up messages for added versimillitude,

Niall
(owner of an extremely expensive quasi-brick)