I followed this guide by keropi to attempt a conversion of a System 16B 171-5704 ROM board that was formally Flashpoint to Shinobi (set 6, System 16B - unprotected).
https://www.ukvac.com/forum/threads/conversions-guide-for-sega-system16b-5704-romboard.65713/
I first removed the FD1094 Flashpoint CPU and replaced it with a confirmed working 10MHz 68000 CPU. I then burnt (and verified) the required ten non-JEDEC EPROM's (ST M27C1000) and a M27C256 for the Sound CPU and installed them in the ROM board. Finally, I configured the jumper settings as per the documentation for the Shinobi conversion (S2 S3 S6 S7 S9 S11 S13 S15 S17 -> CLOSED) and upon power on I was greeted with a black screen.
I initially thought that perhaps the replacement 68000 CPU was bad, so I swapped the ROM board with a working Altered Beast ROM board and the board booted straight away. I then swapped the converted Shinobi ROM board back, this time swapping the A5 and A7 Main CPU program ROM's from the Altered Beast ROM board. The board again booted to Altered Beast however, using Shinobi assets for the graphics.
I started to wonder if the program ROM's I had burnt weren't non-JEDEC. I then burnt another set of the A5 and A7 Main CPU program ROM's for Altered Beast, swapped the original ROM's out for the burnt ones, powered it on and that also booted to Altered Beast using Shinobi assets. I re-verified the A5 and A7 Shinobi ROM's which both matched, so I'm now at a loss to why it won't boot to Shinobi. The other Shinobi ROM's I burnt seem to work otherwise Altered Beast wouldn't be displaying the Shinobi graphical assets / font characters etc. The main board is using a stock 68000 CPU and Z80 CPU and does not have a i8751 MCU.
I'm now starting to wonder if Shinobi is incompatible with the 5704 ROM board... Does anyone know if this conversion does or doesn't work?