So with the 39SF chips I seem to remember it using more address lines for write commands then the older chips. I found a thread on nesdev where it was discussed a little. https://forums.nesdev.com/viewtopic.php?f=9&t=16029

Not sure that is helpful.

Does any one know why the SRAM was included in the FX Pro cartridge and what features used it?

I did a BIOS swap of an SCPH-7000 with an SCPH-7501's BIOS and it worked. It does eliminate the license data check but the PlayStation screen will still say SCEI as that string is stored inside the HC05. Awesome good to know. The other thing I'm wondering about is if different BIOS revisions have d...

Would it be possible to swap the a NTSC-U/C bios into a NTSC-J system? Assuming that a modchip is also used to defeat the protection on the mechacon would there be any issues?

The price is definitely a bit extreme but if you want a set now.
http://www.retrogames.co.uk/040004/Play ... opment-Set

DTL-H2000's pop up from time to time but it probably makes much more sense to get your feet wet with the Xplorer or psxserial.