SEGA Genesis / Mega Drive Mini 2 Support

[PW5190]

The SEGA Genesis / Mega Drive Mini 2 recently launched, and I've been wondering if ROM extraction from that system is possible. Hopefully someone can work on a new update for Hakchi or Project Lunar, or at least a new tool that can extract all 60 games from this successor, including the seven bonus titles.

Also, since many SEGA CD / MEGA CD emulators require a BIOS to run, hopefully the SEGA CD / MEGA CD BIOS can be extracted from the Genesis / Mega Drive Mini 2 the same way as the games.

The emulation and software side of the Genesis / Mega Drive Mini 2 was coded by M2, the same company who also did the same for the Genesis / Mega Drive Mini 1.

Hopefully one day we can get the files "alldata.bin" and "alldata.psb.m" out of the Genesis / Mega Drive Mini 2 and we can use MArchiveBatchTool to extract the game ROMs and the CD BIOS.

[farmerbb]

The Sega Genesis Mini 2 NAND can be dumped and extracted using the following tools:

hakchi-dumper: https://drive.proton.me/urls/N9H8J8VH64#EQ8METqxOkmO
m2-unpacker: https://drive.proton.me/urls/AQB5GB70P4#E7TlbbladF02

(source: message on Rockin' the Classics Discord)

You will need either:

• A USB-A male to USB-A male cable, or:
• A USB-A male to USB-C male cable with a USB-C female to USB-A male adapter

To dump the NAND:

• Run hakchi.exe
• In the "Save As" dialog, choose a location for the nand.bin file to be saved
• Wait for Hakchi to install drivers, etc.
• When the "Waiting for your mini" dialog appears, ignore the on-screen instructions and do this instead:
  • Switch the power toggle off and unplug power from the Mini
  • Plug one end of the USB-A to A cable into the player 2 port of the Mini, and the other end of the cable into your PC
    (if using a USB-C adapter, the adapter should be what's plugged into the PC)
  • Switch the Mini's power toggle on
  • Hold the reset button on the Mini while plugging it back into power
  • Continue holding the reset button until Hakchi detects the Mini

Once the NAND dump is finished, you will then need to mount it. The easiest way to do this is with WSL2 using the guestmount tool.

Install guestmount using:

sudo apt install libguestfs-tools

Create a directory to mount the image to, then perform the mount using:

guestmount -a /path/to/nand.bin -m /dev/sda7 --ro /path/to/mount

Navigate to the usr/games folder inside the mount, and copy the alldata.bin, alldata.psb.m, and m2engage files to the folder where m2-unpacker is located.

• NOTE: MArchiveBatchTool is not able to extract the Sega Genesis Mini 2's data (due to its usage of 32-bit integers and the fact that the alldata.bin file is over 4GB in size), hence the need to use m2-unpacker instead.

Unpack the archive by dragging the alldata.bin file onto m2-unpacker.exe. The extracted ROMs will be found in the Unpacked alldata.bin\system\roms directory.

In this directory are a mix of files with various extensions:

• .bin files are standard Sega Genesis ROMs as well as Sega CD BIOS files which should all be usable in standard emulators.
• .smd and .smp files are ROMs for the new games exclusive to the Sega Genesis Mini 2. Unfortunately, none of these will run in a standard emulator. M2 has been known to modify their Genesis emulators to add capabilities not found on actual Genesis hardware (see: the 3D versions of Genesis games on the 3DS), so I wouldn't be surprised if this also ends up being the case here.
• .mcd files are compressed Sega CD disc images. These will not work in a standard emulator unless decompressed. I am unsure of exactly how to decompress them, however, others on Twitter seem to have done it (see these tweets from @GMMan_BZFlag and @darkdev1)

[Rot-gut]

@wayWardLam
Greatly appreciate the help. So when I run the Ubuntu command prompt, it's just called "Ubuntu" for me. Do I need it to be "Bash for Ubuntu for Windows"? When I open the prompt, it puts me at "root@DESKTOP-(my desktop name):~#". Is this correct or am I missing something here?

[wayWardLam]

@Rot-gut

For this exercise bash = Ubuntu, you can use the command:

cd ~

to make sure you are where you need to be to start.

[Rot-gut]

@wayWardLam Thanks. The below is as far as I get. I updated Ubuntu and downloaded the latest WSL2 kernel MSI update (dated in 2022 from MS's site).

root@DESKTOP-IAH:# cd ~
root@DESKTOP-IAH:# cp /mnt/c/Users/Rotgut/nand.bin .
sudo losetup -Prf nand.bin
root@DESKTOP-IAH:# sudo losetup -Prf nand.bin
root@DESKTOP-IAH:# sudo mount -o ro /dev/loop0p7 rootfs
mount: rootfs: mount point does not exist.

[Rot-gut]

@wayWardLam Ah! I got it to work! I changed directory "cd" to where the nand.bin was and then followed the following command lines to success (the username:username command lines did not work for me):

chmod u+w /mnt/c/path/to/destination/
sudo chmod -R u+w /mnt/c/path/to/destination/
sudo cp -a rootfs/. /mnt/c/path/to/destination/

Thanks very much for the help!

[wayWardLam]

Noobs helping Noobs! glad you were able to get it to work. I love building up my own ROM collection, much more rewarding than just downloading them

[farmerbb]

Twitter thread with some details on the Sega CD file format used by the Genesis Mini 2
https://twitter.com/GMMan_BZFlag/status/1589100536028352514

[DrAzathoth]

Space Harrier I and II can supposedly be run on BlastEm now. Even though they are called “SEGA Mark V” games, they are actually running on an emulated Teradrive. Can anyone try them out on BlastEm?

Source

If this is correct, the only non-CD game that has yet to be run on emulators is VS Puyo Puyo Sun.

[DrAzathoth]

I tried dumping the Genesis Mini 2 with the instructions and tools provided, but I cannot get it to work. Hakchi crashes during the reboot.

[DrAzathoth]

Nevermind. It works now! My timing with the reset button was off. It seems like this Mini is much more sensitive with the timing of the reset button in comparison to all of the other Minis I’ve dumped (NES, SNES, Genesis 1, etc).

[reubenajohnston]

Why does this hakchi need network access? Is it downloading fes or kernel binary that is executed?

[SolarNyan]

Has there been any progress on making CD games and Puyo Puyo Sun work properly through emulators?

[RealRelativeEase]

There's a Japanese Wondermega BIOS on the MD Mini2 and the Wondermega was supposed to have higher quality audio than other Mega CD systems, but are there any actual benefits to using that one instead of the other JP BIOS versions that were included? The higher quality audio was due to hardware and not the BIOS, right?

[DrAzathoth]

Found the WIP patches for VS Puyo Puyo Sun! Unfortunately, it seems the overseas version does not work, but I included it anyway.

VS_Puyo_Puyo_Sun_patches.zip

[jd213]

Nice, hopefully someone can figure out how to get them fully working.