Is there any way to recover from this? I have no soldering skill, so desoldering the flash is out of the question.
I do have a second Webpal on the way. Would this be of any use?
If you have a second Webpal, you're in business. Start with the virgin flash simm, and connect to gdb. Hot swap the blank flash simm in and complete the upgrade process. I had to do it a few times myself. (Should be more details on the forum--suggest searching for hot swap). Note: there is a slight danger to the webpal and the flash from the hot swap. Do this at your own risk.
The alternate recovery method is to program the flash outside the webpal. Someone built up a parallel port programmer and a simm socket for this very purpose. (I think you'd want to look at http://www.geocities.com/sparcusmaximus/alt_alt_flash.html and maybe http://www.luban.org/Webpal for more details on this method--I never tried it.)
This does point out one bit that always bothered me about wpflash--I would have loaded the entire image into ram and performed a CRC check on it before even touching the flash. Not that I've cared enough to fix the code, however...