Well, I do not have a flex cable, nor do I think my problem is there (I am not very experienced to be sure of that though

).
This is my installation, it's not the cleanest, but I have checked values in diode mode, all of them under 700 and over 400 on all the points. I have also checked continuity to alternative points (when possible), and everything seems to be correct. And last but not least, I have disconnected CMD and RST, and I receive the corresponding error code (I guess they are checked before DAT0, I confess I haven't gone through the code though).
Any idea is more than welcome.