Punch Out Mapper

[Hamtaro126]

According to Disch's docs, or any document related to MMC6, The WRAM Protection bit is included for certain reasons (Anti-Piracy)

The reason it did not last: Nintendo felt like they were doing it the wrong way, and MMC6 was a total fail because of that.

[Dwedit]

I would think a feature like WRAM protection would be more useful for making it so you don't need to hold reset as you press power.

[MottZilla]

I agree with you again. WRAM protection is one method of dealing with the unstable state during power down to prevent trashing SRAM without holding reset. It has nothing to do with "anti piracy".

Some carts like Fire Emblem have some sort of circuit to protect data I believe.

[Bregalad]

Yeah, it's definitely about that.
I've lost my saves in Zelda and Final Fantasy so many times I can't even count - which is why if I want to seriously play a NES RPG I'll use the Powerpak.
I think only the MMC5 and MMC6 have proper protection against WRAM corruption, while the Fire Emblem games used an external dedicated chip for this. Apparently Famicom Wars, which uses the same mapper, does not, so its saves should be as unstable as MMC1/3 games.

As for why the MMC6 wasn't used in more games, it probably have something to do with Nintendo simply not telling 3rd party companies about the chip. They seems to have a tradition about keeping their even numbered MMCs in house, while selling their odd numbered MMCs to 3rd parties....

[Dwedit]

I'm sure the tiny 1K size of WRAM didn't help much either. Why bother with MMC6 when you can have a full 8K instead?

[tepples]

Why bother with MMC6 when you can have a full 8K instead?

Replication cost. If you only need it for save and not for work RAM, it might have been cheaper to use an MMC6 than an MMC3 and PRG RAM.