Corrado Tomaselli dumped an Omega board set with a one byte difference between the existing dump which Chris Hardy says is "Unlikely to be bitrot with such a significant change. Decrypted it looks like a legit bug fix as it changes a branch which incorrectly jumps over a bit of initialisation code." and BrianT says "the set ShouTime submitted has the ROM at M10 as “17” and this set it’s labeled “7” so it looks like Nihon made an intentional fix and differentiated the ROMs".