You know, unless you *really* want a stock CC, you should just leave the 560 board in there and call it good, as you now have the equivalent of a Colour Classic II, which is a much more useful machine than a plain CC will ever be (the CC II has no 10MB RAM limit, a faster CPU, and full 32-bitness, which makes it considerably faster).
Anyway, swapping ROMs is irrelevant here, as I believe they both use the same ROM anyway, and whether it identifies itself as a CC or 550/560 depends on what the gestalt ID is. You *could try swapping them, but I doubt it'll do anything.
There's probably some rotted traces by the SCSI chip. The trick will be finding which ones and getting them repaired.
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