So I was flashing my N9, when the USB cable got disconnected.
Voila, a phone that just won't charge.

(Also, due to a pre-existing issue, the power button doesn't work.)

Now, when I plug the phone into a wall charger or a USB cable, the charging light stays on (without blinking at all) for a few minutes, and then goes off.

Any idea what I could do to fix this?