This is on a 1994 Caprice wagon.
I wanted to make some minor changes and have never had or seen this issue before.
I've flashed it problem free many times using EEHACK.

It gives an error stating something about VPP voltage, that the power will need to be removed from pcm to clear flash code.
So I disconnected the battery for a while and tried again. Same error message.
Lather rinse repeat, but this time rebooted the laptop as well.
No dice, same error, are the flash chips done? Anything else I can try?