Hacking the Atari Flashback 2
(Cartridge Port Mod)
This is the area we will be focusing on. This area of the board is where all of the connections and mods will take place to allow the use of real cartridges on the system.
Locate all 24 Cartridge pinout connections. The board is silk-screened to show pin # for each cartridge port connection, however the above image has all of the solder points highlighted in RED. Points 1, 17, 18, 19 and 23 can be a little difficult to locate and to be certain which one is which, so the above image clearly ID's all of the cartridge point points. These pads are small so take your time. Tin the solder points first to make it easier to attach the wire to each point. Have a desoldering iron on hand in case you accidentally "bridge" two solder pads together.
You will move the Black wire from IC2 to the other side of C4, then at J3 you'll need to add a jumper. I recommend you buy a single pull, single throw (SPST) Toggle switch and wire it across J3, this will allow you to enable/disable the onboard ROM chip. For the IC2 C4 connection a 3 way switch wired to the black wire on the common and one wire to the original location and an additional wire to C4 will allow you to switch from the original wire run to the C4 run. You'll need to drill open 2 holes for your two toggle switches. Its some extra work, but worth it since you'll be able to continue using the 40 built in games and then switch to using cartridges when needed.