Ic U2 the cause of cable not cerified error?

All,

I have seen a post on here abut this but none of the answers really helped me. I have two phones 1 an iphone 5 and the other an iphone 5s. Both arrived dead. I replaced the battery. Phone fired up. In the iphone 5 I plugged in the lightning cable. No lighting bolt by battery so I changed the charge port. Got the " this cable or accessory is not certified and may not work reliably. So I tried a few more cables. 2 of which are known good apple chargers and usb cables that I got from the it guy at my work. Still to no use and I tried the solutions as mentioned. Turn off wait for wheel... Plug in wait 15 minutes. Turn phone off and on dismiss warning. Still nothing.

Now I have an iphone 5s doing the exact same thing. I have noted on this phone if I turn the power off while the charger is plugged in. Then unplug the charger. The device turns on. Now I just tried plugging the phone in while off and it turned on. Still not charging tho. I have not changed the charging port as I am coming to think that both of these logic boards may have chip damage of some sort.

Could the IC U2 chip gone bad be the cause of this problem?

Thanks for your guys help!