Finally I think I found the RCMX86 usb problem, at least in my case.
I think it was the magnetic reed that was close to the switch fan and its magnet and was causing problems with GND.
I moved it a little bit down and it's working properly, no more problems with usb.
I'm also having issues with rcm x86 and usb.
The modchip works perfectly, can boot to both OFW and CFW (5 wires + Optional for RCM accidents), but I'm unable to inject payloads or use goldleaf usb install.
Console charges correctly.
I tried removing the reed switch but got the same behavior.
EDIT: Forgot to say that I'm running Switchboot 1.3.3
Any guesses?
Thanks!