[spoiler]Well... The in-game save function does work!
... But the moemon patch turns Pallet City into Glitch City.
GEN1 GLITCH CITY WITH GEN3 TILESET
Once I exit my house, I cannot enter it ever again. Also cannot enter Rival's house... Nor Oak's Lab. The forced Oak event, where I try to go into Route 1 without a Pokemon (after some difficulty...), will get me into the lab, but I cannot return inside again to deliver Oak's Parcel.
So... The game is unwinnable. Right at the very start. ._.
Just to confirm, I tried the unpatched FireRed rom. Pallet Town was just fine. ._.
Also, I tried my savestate from my previous moemon game. Apparently because that savestate is based on the in-game save function of the previous game... It can't save over into the current in-game save function.
I CAN'T PLAY MY MOEMONSSSSSSSSSSSSSSSSSSS ;~;[/spoiler]