I almost finished building my second multi-cartridge. This one has F8 bankswitching hardware built in. It can hold up to 16 8k games or 16 4k games (gets copied twice to the cart so when a bankswitch occurs it does not affect the game) After cleaning up the code of the pc connectivity tool that goes with the cartreader I could easily make changes to the bankswitching code. The cartreader still only supports F8, but F6 is pretty easy to implement too. I do not own any F6 games to test it with, so I am going to have to get some F6 games first. It seems like I don't have to make any hardware modifications to the cartreader, so I will solder up a prototype and put it in an enclosure soon!