Killer Instinct Dual Board KI + KI2 arcade PCB

Here are the steps to achieve the mod:

Important: you need a KI board, the KI2 board won’t work.
In the past, Midway offered an upgrade kit to operators that gives them the ability to convert an original Killer Instinct to KI2. The kit consisted of a set of 8 sound roms, a boot rom, a hard drive and his infamous IDE conversion board. While a KI board will work with the upgrade kit installed, this won’t work the other way round, ie. a KI2 board wouldn’t work with a KI HD and roms set.
Hence, it’s mandatory to have a KI board.

DogP, from the Arcade Projects forum, provided a patch for the boot rom that gives us the ability to run the KI2 HD and roms on a KI board without the need of the (very rare) IDE conversion board.
Download the patch from DogP (link provided at the end of the description) and patch the “KI2 conversion Any IDE” rom.

To switch from one disk to the other I used an IDE 44 pins to SD converter (https://www.aliexpress.com/item/40003...) with a 2in1 microSD adaptor (https://www.aliexpress.com/item/33040....

For the sound and boot roms you must use eproms with double the size of the original ones. Original roms are 27C040s, so you’d need 27C080s.
Concatenate the rom files: do a copy /b ki_u10.bin + ki2_u10.bin ki_ki2_u10.bin for each rom and burn them to the eproms.
To switch from one bank to the other you must switch A19 (pin 1) from high to low. Insert the eproms into the PCB but leave pin 1 outside, daisy chain all the pins hanging out and connect them to a switch so that one position of the switch connects those wires to ground, and the other position of the switch connects them to 5V (tap them from the IDE adaptor).

I used a DPDT switch to switch the eprom banks and the SD card in the 2in1 adapter at the same time.


Here are the links:

A few detailed pictures of my install https://www.arcade-projects.com/threa...

The thread, starting from the last 2021 updates from DogP https://www.arcade-projects.com/threa...

The patch https://www.arcade-projects.com/threa...