Hi I have got a galaxy s with 2.2 installed. It generic sim free phone i think. I am having a issue whereby the battery indication on the top bar is not accurate/same as the % in settings or other apps See pic of what i mean I have tried numerous draining/100% charges while off. but still the same I have heard of rooting a phone and deleting the battery stats file. but not sure i want to root the phone. can you unroot later on? any ideas?