Whats with all these NES MMC chip hacks

[Deleted User]

I've been browsing romhacking.net and there seem to be a number of NES ROM hacks that do nothing but change the MMC chip used by the game.

http://www.romhacking.net/hacks/2667/
http://www.romhacking.net/hacks/2680/
http://www.romhacking.net/hacks/2686/
http://www.romhacking.net/hacks/2690/

I could go on...

I don't understand the purpose behind these hacks, though I've come up with several posibilities.

- It may allow romhackers to make more complex hacks
- It could be played on an emulator or flash cart that doesn't support the game's orginal MMC chip
- Someone making a repro cart can have an easier time finding an appropriate doner cart

 

[FAST6191]

There is a thread over on romhacking.net forums covering this
http://www.romhacking.net/forum/index.php/topic,20985.0.html

Short version is the NES was not a great system as is so it had its carts carry hardware to expand its capabilities (storage, sound, saving...) with said expansion methods usually being given the term mappers ( http://wiki.nesdev.com/w/index.php/Mapper ), see also why NES flash carts and emulators will often list the mappers they support. Such a thing is also why certain SNES games are hard to use with flash carts or certain emulators. Back to the NES then some in the MMC family are often considered the best of them all (they are good but best is debatable for me) as it comes with extra abilities. Converting mappers was once considered one of the harder hacks you could do and there is still scope for it to be, however it is possible to change enough stuff to have a flash cart/emulator load it up as one which is what most of these are.
It has been argued that if you are good enough to use this then you are good enough to do it yourself and that it would not take long. To that end yeah they are pretty useless, your three options being about the only uses worth speaking of.