Mega Drive country switch mod

[Pyrite]

What exactly is the point of the country switch? I thought the only protection was the cartridge slot which can be bypassed with either a cart adapter or by trimming the plastic. I've broken the 157 chip leg so I can't do the switch mod on my MD2 anymore. I did the 50Hz-60Hz mod successfully though, you can even switch while playing, the difference is astonishing to say the very least!

 

[ExCyber]

I thought the only protection was the cartridge slot

It's the only actual "protection" that's built into the system. However, there are register bits that a game can read to find out:


1) Whether the Genesis/MD is Japanese

2) Whether it's running at 50Hz or 60Hz


Games can read these and do whatever they want with that information. Some use it to refuse to run on a different-region console. Some use it to tweak timing and/or VDP settings for 50Hz systems. Some use it to display a different title screen so that one ROM can be sold in multiple regions under different titles (e.g. Revenge of Shinobi / The Super Shinobi). If someone wanted to, it's entirely possible to make a Genesis/MD cart that runs a completely different game in each region.


Also, the various region variants of the Sega/Mega CD firmware do check these registers to make sure that the attached Genesis/MD matches the region of the SCD/MCD unit.

 

[Pyrite]

It definitely has other advantages that I didn't take into consideration, I deducted that since it turns the image into black and white when running in 60Hz the Mega Drive was running in NTSC mode so it wouldn't have a problem running US/JP games as is, good thing I have a spare MD2 and MD1 laying around so I can install the country-switch on those next time.