Power button still not working after replacing flex

So, my power button wasn't working. I got the usual symptoms: first it would work when pressed on one side but not the other, then it would only work every now and then, until finally it stopped working completely.

I bought it on another country, plus it's jailbroken, so I really didn't want to go through an endless argument with Apple for my warranty only to end up (if I win) with an updated un-jailbreakable iOS.

So, after a few weeks of research, everything pointed to the flex power-volume-mute cable. I ordered all the parts online (I got the Pro Toolkit and the magnetic mat from here, awesome set), and after a month I finally got everything ready.

I removed the flex cable and switched it for a new one, and then assembled everything back. Phone works exactly as before, power button still doesn't work. I had ordered a replace power button just in case, so I opened the phone again and also changed that. Still the same.

Mute and volume buttons works like a charm as they've always done, but power button is completely dead.

anyone has any idea what could be happening this? What are the chances of the new flex cable being faulty exactly on the same button? Should I look into something else?

I got 2 replace flex cables (I don't know why, I bought one, paid for one, received 2), but I don't want to go through the whole replacement process blindly.

Any help is appreciated.