20 - 30 minutos
The phone "worked" fine as an iTouch without a Sim card installed, but when the card was installed the phone would reboot sporadically. Upon review it appeared that the back of the phone was pushed out a little more than expected.
The repair was seamless and fast. Upon getting to the battery it was notice that it was puffed up, the battery was pressurized thereby putting pressure on the case and on the phone internals.
If the phone asks unusual then it is probably the battery, unless you know otherwise. Replace the battery with a quality replacement from ifixit.