MegaSD

The MegaSD is an all-in-one flash cart for the Sega Genesis / Megadrive that plays games from the Master System, Genesis, SegaCD, and 32X (with 32X hardware).

Firmware can be downloaded here (Current Firmware is 1.03 R04) Please note that you need to register your device and if firmware is not present after registering it means you are on the most current firmware already.

Manual is located here

Set-Up

• Any storage size MicroSD card should work as long as it is FAT32 or ExFAT formatted. TerraOnion generally recommends avoiding Samsung branded cards as they have been known to cause issues on their devices. Sandisk is the preferred manufacturer.
• CD games must be in their own folders. The folder name dictates the name that is displayed in the SSDS3 menu for CD games. Nested folders are fully supported for both CD and cartridge games.
• Sega CDX, X'eye, Wondermega, allow cartridge based games to load but CD games are disabled due to potential bus conflicts that oculd damage your original hardware.
• If you have a SegaCD/MegaCD attached while using a MegaSD CD games are disabled.
• Similarly CD games cannot run through a 32X. Using a MSDEXP can bypass this limitation.

Usage

• There is no reset function on the SSDS3 and while there is a hot-key (In Game Trigger) to accomplish this it is not compatible with a sizeable portion of the library. As such you will need to power on and off your system to return to menu
• You can assign a bios in the SSDS3 options menu. For the greatest compatibility TerraOnion recommends using either the US or JP 3.0 bios.
• Turning Arcade Card emulation on in the options should be considered a default. It will turn off automatically behind the scene for games that do not need it.
• Seek time emulation allows games to run at a simulation of the speed of an actual disc. If you have problems with a particular game try toggling it on and off. In most instances leaving it on works best. Also let the TerraOnion team know of your findings.

Game Compatibility & Known Issues

• The In Game Trigger option which allows a user to return to menu does not function properly in a large percentage of games, it causes crashes or other issues. It is recommended not to use this option or at the very least realize it is experimental.
• Certain BVM CRT models do not seem to like the PC-Engine video output and have sync issues. This is not an SSDS3 issue unfortunately.
• Sherlock Holmes: consulting Detective Vol 1 & 2 has audio/video desyncs
• Popful Mail has corruption in the 2nd Intro movie

Tips & Tricks

• SuperGrafx games can only be played when the SuperGrafx is attached to the SSDS3. However, the SuperGrafx has certain game compatibility issues that require the switch to be in the "II" position to work. A list of known problem games can be found here
• You can have the SSDS3 override the bios on a "per game" basis. To do this simply drop a specific bios into the same folder as your Game CD image. This is useful for the handful of GamesExpress titles as well as the earlier version of Altered Beast that only ran on the 1.0 bios.
• You can dump your own hu cards. Instructions are here