Okay, if all the files contain identical code, and the 4MB file is identical to the 3MB file but with stuff at the end, that pretty well answers what to do next. Take one of those files and program it onto chips and then solder the chips down.
I am actually happy that the 4MB file has 1MB of padding at the end. I was worried that the 3MB file might do something weird like have 1MB of padding at the beginning, which the dumper ignored, and then the 3MB of content in the top addresses. The 4MB dump having 1MB of padding at the end pretty strongly implies that the usable content starts at address 0 of the ROM DIMM.
The reason I had concerns about that was because of the bizarre arrangement of the PLCC chips providing hardware boot code and the toolbox on a separate DIMM. This leaves me wondering what the logic board is doing. I guess it must put the two types of storage at different addresses.
Anyway, there are about half a dozen ways/reasons I can think of that this still wouldn't work, but I only see one way in which to proceed at this point based on the information and resources we have available to us. So, as soon as I can clear some time, that's the direction I'll go.
My work bench is even more accessible than the last time I did any work on this project. I've actually spent close to two years cleaning up junk. Too much junk! Of course, with an eight-year-old under foot, the actual clock time spent on the neatening is much less than two years elapsed time implies....
I am actually happy that the 4MB file has 1MB of padding at the end. I was worried that the 3MB file might do something weird like have 1MB of padding at the beginning, which the dumper ignored, and then the 3MB of content in the top addresses. The 4MB dump having 1MB of padding at the end pretty strongly implies that the usable content starts at address 0 of the ROM DIMM.
The reason I had concerns about that was because of the bizarre arrangement of the PLCC chips providing hardware boot code and the toolbox on a separate DIMM. This leaves me wondering what the logic board is doing. I guess it must put the two types of storage at different addresses.
Anyway, there are about half a dozen ways/reasons I can think of that this still wouldn't work, but I only see one way in which to proceed at this point based on the information and resources we have available to us. So, as soon as I can clear some time, that's the direction I'll go.
My work bench is even more accessible than the last time I did any work on this project. I've actually spent close to two years cleaning up junk. Too much junk! Of course, with an eight-year-old under foot, the actual clock time spent on the neatening is much less than two years elapsed time implies....