I can't take any financial donations. This is a hobby project and at the moment I can work on it as and when I get time, or just give up completely if I get bored with it. If I take money from people then I'll feel obligated to make progress and produce results. Besides which, It's not just me working on this now. There are lots of other people making valuable contributions of time and skills to the project and increasing our communal knowledge base.
Anyway. Something else I've been meaning to post for a while.
I was originially thinking that the solder tags on the TCU board were for an EPROM upgrade and that maybe the TCU used the same type of EPROM chip as the ECU. Now I think I was wrong about that, like so many other things
. The wiring on the TCU board does not match the 27C1028 pinout. There are wires going to pins that as designated as "no connection" on the 27C1028 datasheet. In addition there is no obvious resistor to cut to enable the upgrade chip like there is on the ECU.
The stock EPROM on the TCU is a small surface mount 27C256. The solder tags seem to be wired the same as the stock ROM. I think maybe the idea was during the manufacturing of this board they could choose to either use a surface mount EPROM or a DIP-28 style EPROM interchangably.
So, my latest theory is that in order to upgrade the TCU, you have to use a DIP-28 style 27C256 EPROM, and disable the surface mount EPROM. I'm not sure whether you have to unsolder it completely or whether cutting the "chip enable" pin will do the trick.
This is probably a good thing. The 27C256 is probably easier to get and program than the 27C1028 used in the ECU.