Well for one, understand the difference between reseting to factory defaults and reprogramming an engine with a file- that only applies to PS2 and PS3 engines.
PS1 is only reprogrammed by replacing the chip.
Reset to factory defaults- the default settings contained within the programming of that chip can be accomplished using a Z4000 transformer.
But before you even do that, you have to know that you have a good PS1 battery and it's working before any other step in the troubleshooting process.
So again, confirm you inspected and/or replaced and know that you in fact have a working battery subsystem or all of this is a waste of time.