Thread opened by request.
Sorry I never responded. I must have missed your post. The double posting rule pertains to short periods of time between posts. If no one seems to respond within a week or two, feel free to double post. Also feel free to PM me directly. I like to keep all discussions in this thread for others to find, but I may not see every post even if I would like to.
Really glad you got your Cotton cart working on your own, you must have learned a bit from that experience.
As for PS4, it sounds like you are using two different "types" of saving-boards. PS4 uses a large SRAM chip while the original Wily Wars uses a small EEPROM to save. These are not compatible with each other however, There is a patch for the Wily Wars ROM that changes it to use SRAM instead. This makes it compatible with SRAM type boards.