Resettng an android device with non-removable battery
I had to remove the battery from my O4X several times already, as it didn't respond to anything else – so I can see your concern: What to do if the battery cannot be removed then? As to my experiences, devices with a non-removable battery have a reset hole, which serves exactly this purpose: poking it with a needle (or tooth-stick, or something similar) disconnects the battery, as if you had removed it. So the only disadvantage left is you cannot replace the battery (say, with a backup you took along).