Accessory not supported, dock replacement does not make a difference.

Hello,

First, let me give you a little bit of context of the problem.

I am semi-experienced in Apple cell phone repair and know how to replace screens, batteries and that kind of stuff.

To further expand my skill, I have second hand brought an iPhone 6 Plus with Wi-Fi problems and the infamous touch disease.

To solve the problem with the touch disease I have brought a new motherboard from Aliexpress and have swapped it.

At first it look like everything was working (No Wi-Fi issues and no touch disease problems) but when I plug in a charger I immediately got the “accessory not supported” error.

Of course I have tried all the default steps;

• Different chargers (Including Apple original) > No difference.
• Different cables (Including Apple original) > No difference
• Even connected with the original USB-C to Lightning cable connected to my 2018 MacBook Pro I get the error, while there is no problem with iTunes /Xcode data transfer.
• Recovery of a fresh iOS trough iTunes also does not make a difference

So I have thought it was the charging flex cable (from opening it up to replace the motherboard, it looked 3th party to me and not original Apple).

So I have ordered a new charging / dock connector flex cable and swapped it, but it still gives me the error. Also when I again try the above steps and does not make a difference.

The only strange thing I have noticed is when I try the steps to enter DFU mode;

- 3 Sec powerbutton

- 10 Sec power- and homebutton

- 5 Sec homebutton

The screen immediately lights up with the Apple logo when pressing the powerbutton, instead of waiting 3 seconds.

Also when powered off the device is charging, but not when powered on.

Do any of you guys can give me a clue to go from here and/or what to try next to fix it?

Thanks in advance!

Best regards,

Schootje