This is a problem with the battery data being conveyed to the logic board. In the 5s, the BATT_SWI line went through a commonly knocked off filter to cause this problem, and here on the 8/8p/X the battery data has been reconfigured as an HDQ interface that goes through two small mosfets and then the tigris chip passes it to CPU. Your MOST likely problem if this happened at a screen chance is pry damage—knocking off the mosfet or damage to the battery connector or battery itself. Any microsolderer can help you fix this.[br]
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Jessa