892: #ifdef WORKAROUND_RAINBOW_B
893 uint8_t *rom = memregion("maincpu")->base();
894 ...
89X rom[0xf4000 + 0x03d8] = 0x00; // - - - - - unblock BIOS auto boot
89Y rom[0xf4000 + 0x8aa] = 0x01; // - - - - - JMP FAR 0000:1000 (could be a Rom bug)
89Z #endif