Six chip STM (fitted with six chip 1.4 in this case) note that the very top ROM socket is offset to the right slightly. The extra chip under it is a Dallas Real Time clock.

There are two blue wires that need connecting to the ROM area, and as I will have empty sockets, I'm adding pins. Note: I should have used smaller pins really, as these have opened up the tiny clips in the ROM socket, which will need fixing if I ever go back to 'stock'

Soldered.

Initial fitment. There are two boards, a 'master' and 'slave' - the Master has more wires coming from it, including two that need to go to two legs on the 68000

Wires carefully soldered to the processor

I made an error! In my excitement to fit this, I forgot that the early STM machines have the ROM sockets in a different order, so when I tried to boot with the chips in the earlier pic, I just got a white screen and no disk activity. Swapping thr boards over made it work.

Working 1.4 :)

One thing to note is that the original shielding will no longer fit. Two options here - trim the shielding (the hole in the pic is the already present factory 'trim' for stock ROMS) or remove the sockets and solder the new boards directly to the STM.