[vanadium]

If you have a Neo Geo AES (home), MVS (arcade)or, more recently, Neo Geo CD, this is a table-stakes modification that unlocks quite a few features, including bypassing region restrictions which were prevalent when it came to removing the censorship prevalent in U.S. versions of their games (e.g., blood, et al).

I felt it worthwhile to make sure I ordered it straight from the source for my AES, which enables ongoing support.

[Villodre]

I wholeheartedly agree: some are against modifying these retro systems, but this opens up a whole world of possibilities.

I also got mine (AES and CD) directly from the author but he no longer provides upgrades via postal mail. Instead, he can send you your customised one by mail and flash it yourself.

[dleslie]

It's really not a serious modification, since the Bios sits in a socket and isn't soldered on.

And besides, very few functioning MVS systems haven't had some form of modification; at the very least, the timebomb-of-doom battery has likely been replaced with something that won't eventually leak and dissolve half the board.

[jchw]

Interestingly, it looks like it is no longer sold and the terms disallow redistribution.

If it’s just something where you can get an EEPROM and flash it, it would be interesting. On the other hand, it looks like the EEPROM on the Neo Geo CD might be surface mount. Not my favorite stuff to work with.

[dleslie]

The creator just isn't interested; but they've given the go-ahead to several other folks to sell it.

[badlucklottery]

>this is a table-stakes modification

Yup. Even the Neo Geo MiSTer core supports it because, like you said, it really is considered table stakes in the Neo Geo community and would be a ton of work to reproduce.