Reserved System Registers
MIRE uses I/O mapped registers 0xD0 through 0xD4 to communicate with the PIC processor that controls SD card access. Definitions of these registers are not necessary to use the MIRE and users are highly discouraged from modifying them in any way.
In case these register ports conflict with add-on devices, setting bit to of I/O port 0xE2 will disable them but will also disable some SD card access: emulated floppy access will still work but the FAT filesystem will be inaccessible.