Right. I've spent ages arsing about (both my PAL SNESes are a bit temperamental, which didn't help :/ ) and I *think* this is how it all works.
I have my own Mario RPG cart which, even before modding, worked both in a US SNES with an enabled territory lockout chip, and in *all* my SNESes with the territory chip disabled.
I've borrowed another Mario RPG cart which, as mentioned, has had pin 127 broken off entirely.
First thing I found is that none of the 3 import adapters that I've tried would work with Mario RPG - the cart had to be connected directly to the SNES in order for it to work at all.
If anybody has a copy of Mario RPG which they can't get to boot, you first need to try it connected directly to the SNES - you may find it'll work like that.
Obviously if you have a PAL SNES then you'll have difficulty getting the cart to fit - you'll either need to remove the cartridge shell and insert the bare pcb, remove the top shell of the SNES, widen the cartridge slot of the SNES shell, or else try and put the Mario RPG pcb into the shell of a PAL cartridge.
There are 3 possible states for pin 127:
1. Grounded. Pin 127 was originally grounded in both carts that I've got here - in this state, the cart will boot with a US/JP *functioning* territory lockout chip. My cart also booted with the territory lockout chips disabled, but I gather that not all versions of Mario RPG will do that.
2. Floating. With pin 127 left floating, the game will boot on a PAL SNES with a *functioning* territory lockout chip. (My cart still boots on my region-modded SNESes, but the cart with the broken pin 127 does not - it only works on the PAL SNES w/working region chip).
3. 5 Volts supplied to pin 127. In this state, the cartridge booted on a SNES with a disabled territory lockout chip, but refused to boot on any SNES with a functioning lockout chip.
Here's a (very blurry!) pic of my cart after the mod:http://img.photobucket.com/albums/v204/ret...MarioRPGMod.jpg
I'm truly sick of Mario RPG after all this messing about - if anyone else wants to try the mod and post their findings here, that would be great.
If anyone wants to take my ramblings and write it up properly, then that would be even *more* great.