Ver 4 PS2 no gap rom vs gap rom

[razzziel]

Does anybody's US version 4 ps2 with a GAP rom work 100% (ps2 + dvd backups)? If so, what is your date code? (located under s/n on rear ps2 label)
I have the NO GAP rom (the one inside ps2's that don't work!) and my date code is 1C. We "no gappers" (or at least the ones with 1C) seem to be incompatible with neo4.
I've read about it in the forums and even my supplier mentioned something about it.

Could it be that they sent us the wrong neo4's (for versions 1-3) instead...?

I think that all the problem neo4's (that have ok wiring and solder) have to do with this damn NO GAP rom!

What do you all think...?