linuxmd

Linux for the Sega MegaDrive

Is this a joke?

No

What do I need?

• A Sega Megadrive
• Mega EverDrive Core or Pro (pro is untested) (See: https://krikzz.com/our-products/cartridges/)
• USB cable between the EverDrive and your PC
• Time to burn

Will this work on an emulator?

Probably not, the emulator would need to emulate the EverDrive's special SSF2 mapper that gives use 4MB of RAM and the EverDrive's protocol that allows the MegaDrive to load files from the SD card.

Build instructions

• Run ./buildtoolchain.sh to build a toolchain. This uses buildroot but we do not build a root filesystem with it. buildroot is the least painful way to get a m68k-linux toolchain that can produce usable binaries for 68000.

• Run ./builduboot.sh to use the toolchain to build u-boot.

• Run ./buildmedtool.sh to build medtool to interact with the everdrive for serial console.

• Run ./buildlinux.sh to build the linux kernel image. (NOTE: at the moment this does not produce a workable image).

• Run ./buildrootfs.sh to build the rootfs erofs image.

TODO

Boot instructions

• Copy u-boot/u-boot.bin, linux/vmlinux.lz4, smolutils/m68k.erofs to your EverDrive SD card

• Power up the Megadrive

• Connect the USB cable to your PC (It might be OK to connect it while the Megadrive is off but I had issues with it)

• Check your dmesg to make sure the EverDrive is detected. You should see something like this:

[1135618.045606] usb 3-2: new full-speed USB device number 5 using xhci_hcd
[1135618.255415] usb 3-2: New USB device found, idVendor=0483, idProduct=5740, bcdDevice= 2.00
[1135618.255428] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[1135618.255430] usb 3-2: Product: Mega EverDrive
[1135618.255432] usb 3-2: Manufacturer: STMicroelectronics
[1135618.255434] usb 3-2: SerialNumber: 00000000001A
[1135618.307393] cdc_acm 3-2:1.0: ttyACM0: USB ACM device
[1135618.307472] usbcore: registered new interface driver cdc_acm
[1135618.307475] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

• Connect medtool to your EverDrive in terminal mode:

./medtool/medtool -p /dev/ttyACM0 -m terminal
Opened serial port /dev/ttyACM0
data out, 4 bytes -->
0x2b 0xd4 0x40 0xbf 
<-- data in, 4 bytes
0x5a 0x05 0x25 0x00 
core
Creating socket and waiting for connection (minicom -D unix#/tmp/medtool)

• Do what it told you and start minicom with it connecting to the unix socket for medtool

• In the EverDrive menu select u-boot.bin hit a button, and then hit start game

• Wait a little while and you should see u-boot appear on in minicom:

Welcome to minicom 2.10

OPTIONS: I18n 
Port unix#/tmp/medtool [?]

Press CTRL-A Z for help on special keys

md
!
a
b
c


U-Boot 2026.01-00647-g39f62d87171b-dirty (Feb 14 2026 - 16:46:36 +0900)

DRAM:  3 MiB
SR is 0x2710
copy from 00000000 to 002d9000, 0x265d0 bytes (reloc_off 0x002d9000)
copied from 00000000 to 002d9000, 0x265d0 bytes (reloc_off 0x002d9000)
clearing new bss from 002fd000 to 002ff5d0
Doing relocation 
Relocation point of no return, new SP 0x00197a30, jump to 0x002e1b1a
Core:  4 devices, 4 uclasses, devicetree: embed
Loading Environment from NVRAM... *** Warning - bad CRC, using default environment

In:    serial
Out:   serial,vidconsole
Err:   serial
=> 

TODO