Genesis/MD/Sega CD/32x Region Bypass Tool 1.1a

Region lockout bypass tool works on Genesis, Mega Drive, Sega CD, and 32x ROMs. It will try and patch your ROM so that it will work in any region. Also has a checksum fixing button to try and fix the checksum after patching (if needed).

Features:

Uses pattern searching to try and find 4 different types of region checks in the ROM.
If it finds any region checks, it will display the ROM addresses where they were found.
Will display what regions your ROM is for. Will work with the original style region letters (JUE), or with the new style (1 = Japan, 4 = USA, A = Europe, etc).
The program does things differently than what you’d expect. If it finds a region check in the ROM, the region that is selected will actually be the region of the console that the ROM will see when it does a region check. In other words, it usually doesn’t change the region of the ROM, it changes the region of the console in the ROM. This almost always makes it run in any region.
If your ROM is for a single region and the program finds at least one region check in the ROM, it will automatically select the best region so that your ROM will be region free, and work in any region.
Depending on the game, you may need to experiment with the 3 different regions to see which ones work. Sometimes your game will run a little faster or slower after changing the region (50/60hz issues). You can try the 3 different regions to see if you can get it to run at the correct speed.
If the program doesn’t find any region checks in the ROM, then it will only change the region letters/codes in the ROM header (at 0×01F0). Some games only use those region letters in the ROM header to determine the region, so that will often work.
Writes information to an unused part of the ROM header so if a previously patched ROM is opened again, the program will know what it did before.
When patching, you can decide if you want it to create a new ROM or not. If you do make a new ROM, the program will automatically add “Patched” to the end of your file name, along with the letter of the region it was patched to. This makes it easy to remember which file was patched, although you can name the new file anything you want as long as it’s not the same as the original file name. This keeps your original ROM safe.
Has a “Fix checksum” button that will try and fix the checksum of your ROM. This can be used by itself if you have a ROM that just needs the checksum fixed.
Has an improved method of finding Electronic Arts (EA) checksum routines, and should have a 100% success rate with EA games that use a checksum routine.
Displays the starting ROM address of EA checksum routines. Tip: Use that EA ROM address, along with a value of 4E75 and enter it into a Game Genie code converter program to get a Game Genie master code for that game. If you click the “Fix checksum” button, it will patch that 4E75 into your ROM for you.
There are a few Help/info buttons in the program with lots of information.
There are lots of different ways to do region checks and checksum checks, so this program will certainly not work on every game, but it seems to have pretty good compatibility.
Will work on Sega CD games, but have only tested it with Sonic CD (USA) so far. The program found several region checks in the ROM. Changed the region to Europe/PAL and when playing on Gens emulator (with country set to USA), the game ran slower, which means that Sonic CD does use the region checks in the ROM to determine the region. Still need to do more testing with Sega CD games.

https://www.romhacking.net/utilities/1687/