I've read all the comments in this thread, and, frankly, there are not many suggestions other than "don't do that" or "do something else," at all, aside from my own. I've even suggested a couple that probably won't sell, though they are low-cost and easy. From among my suggestions, I'd say that using the SRAM, or programming the EEPROM directly from the PC parallel port, are the front-runners where easy and likelihood of success are concerned.

First of all, I don't disagree with you, in that he probably would do fine with an ISP part. Sadly, he's "hard-over" on the use of the parallel port, and the old Intel MCU, together with that obsolete (?) EEPROM, all of which will only serve in 80C31 mode, that he's already got.

Clearly, we've got a case here, wherein a guy wants to use THESE parts, so no amount of persuasion will change his mind about that. It's like the guy who was born in 1948 and therefore wants to restore an old 1948 Ford. He doesn't want to buy a new Ford, even though it would cost him $100k less. There's no point in discussing other options. He wants to know how to get THAT engine to run. He wants to know how to make THAT body look like new. He wants to know how to get the chipmunks to move out of THAT upholstery.

The only thing those of us who might "know better" can do is thumb our noses and tell him what we can that will help him do what HE wants, however inefficient of time, hardware resources, and cash, it may be.

Now, I've recommended at least one way of doing what he wants, without buying someone else's solution, though there may be easier ways. I doubt they're much easier, though.

RE