speaking of broken systems, I tried to fix jaguar today (bug 1766). I came to the conclusion that somehow jaguar bios is loaded with the wrong endianness: if you start any jaguar cart, you see immediately that the CPU reads an illegal instruction rather than jumping to E00000 as expected.

culprit could be either ROM_LOAD (cojag uses a REGION32_BE) or the part of MACHINE_RESET(jaguar) where the first 0x10 bytes of the bios are copied to the shared RAM.

However, I haven't managed to fix it (probably because I used the wrong combination of ROM_REGION/ROM_LOAD....)
Has anyone any suggestion about this?