Thanks for the reply, daveshooter... I'm currently trying a "do over", though it's a bit different as the PS3 no longer boots at all. In the original guide, there is some assumption that the PS3 you're working on is actually functional to start, and mine just starts up and shuts off.
However... upon trying to ignore that fact and fake it a bit, it did manage to blink the power button repeatedly with the PUP and diag file 1 on a USB stick... and after a time, when i tried to continue and go to the next file, the USB stick had a log file added to it... so clearly it is "attempting" to do something.
Though the second diag file still resulted in the same dead PS3 on retry. I'm currently checking out a different set of DGF files to see if maybe the files I have are part of the problem. The original guide kinda pointed into the ether for where to get those DGF files, so maybe my original set are causing an issue.
Either way, the machine is now running a 4th or 5th attempt through this process, so hopefully one of these times it'll take. If not, maybe I'll check into getting an E3 as I'm currently just working with a Teensy++ 2.0 and a standard USB Memory Stick.
One question though: when you say "You MUST eject the USB from the pc every time you put it in the pc, some times mount it 2 or 3 times and eject it. Trust me it works"... what is it you mean?
I've tried using both Mac and a PC running Vista to get these files onto a FAT32 USB Memory Stick, and as far as I know, I haven't had problems simply "ejecting" on Mac or "Safely Removing" on PC. Is there something about getting the files onto the USB stick, or ejecting it, that is out of the ordinary here?