Same issue on the Atari ST; the custom chips just permanently mapped the first 8 bytes of RAM to the first 8 bytes of ROM. The remaining vectors stayed in RAM.

Same issue on the Atari ST; the custom chips just permanently mapped the first 8 bytes of RAM to the first 8 bytes of ROM. The remaining vectors stayed in RAM. Other systems I've seen just put a ROM at 0x00000000 and do an indirection (just a couple instructions of overhead).