Instead of migrating every new feature (32 char menu, exit function and new bankswitchings) to the UnoCart we should aim for a common code base.
It would be easier if we re-implement the SD card code into the PlusCart code (to the submenu "SD-Card" ?) and use switches to compile for the UnoCart or the PlusCart.
we also could use a more generic approach and switch the hardware differences directly, so we could build for:
using lower or higher GPIO port for the data bus