1708 controller restarting constantly

Hi folks. I’m an electronics engineer but unsure what the common faults are for this issue. I had a wireless original 1708 controller, it stopped connecting on wireless (dead batteries) so I plugged it in to USB, it said it needed an update, so I thought yeah why not. 87% into the update it disconnected. Now it reboots or resets continually while plugged in. It appears on screen saying update required but then disappears, does this over and over.

The Xbox button on the controller glows bright, it appears on screen, then goes dim, which is when it disappears. No connection when not on the USB now at all. Even with a new battery pack.

Is this likely a capacitor faulty and if so, on the power board or the analogue board? Or does anyone know different?

I tried the PC app and it does the exact same thing.