I wasn't even using maprom at the time, just booting clean and it was screwing up.
Last night I removed the mod on the DMA chip, fixed the UltraSATAN partition again (using dosfstools under MiNT on the TT) and replaced the Goex with an Epson SMD-380 so I could use a floppy with HDDriver 10 on it. The system started behaving properly again.
This morning before I went into work I checked the machine again, booting into EmuTOS. The first time after switching on, PANIC: Exception 14 but after a reset it was fine and everything seemed to be working properly, so I started Gembench on a loop. By the time I got back, so as to work the rest of the day at home, it had gone through 88 loops without error.
Anyway, I think I'm going to order a whole load of 2.2K and 10K matrix resistors and replace all the pull-ups on the main circuit board. I was trying to leave the machine as close to stock as possible hence the reluctance to change them. I think I'll also solder my board onto the main board and get rid of that horrid turned pin socket. They never give very good connectivity when using pins. This will lower the board by about 5mm. I've been leaving this as really I want to get the SMD 68030 board soldered onto the TF536 first, then the TF536 soldered onto my board before soldering it onto the motherboard so as to reduce the height by the maximum amount, but the sockets are too unreliable.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.