DoDonPachi DOJ Black Label Save hack : Add save functionality to your DOJ WL PCB with this simple ROM swap. Do not use on an original DOJ BL PCB. It might work, but it will stop the original EPROM from booting.
There are a couple of known issues with this ROM. Obviosly it will not save without the battery. Also, if the NVRAM contains data that that the high score table does not understand it will crash. The brown switch on the PCB should not be used. Whilst it should clear the NVRAM, the 'clear' state cannot be verified and my leave spurious data which will crash the PCB. Factory resetting the PCB from within the test menu *may* return the NVRAM to a usable state but cannot be guaranteed.
Note; If the PCB is powered off whilst the game is saving the NVRAM contenets may get corrupted.
If the NVRAM does get corrupted the modified DOJ BL EPROMs or original WL EPROMs will still work without issue.
Download, extract, burn to a 27C160 EPROM and mount in position U36. If the game boots to a garbled or black screen enter the test menu, factory reset [9. DEFAULT] and try again.
If the game hangs with strings of text down the left hand side then the NVRAM is unsuitable for the hack. A factory rest is unlikely to help but probably worth a go. Inserting coins and hammering the start button on the country warning screen may also help but it's not guaranteed.
All credit for this hack goes to austere.