A phone or tablet problem starting right after an OS update, a new case/accessory or a restored backup should be checked against that change first. For iPhone touchscreen input, first remove charger/case/protector for a test and draw across the full screen in a simple app.
What this covers
- iPhone touchscreen input with this exact failure state
- Diagnosis across one app and screen region versus protector, moisture, accessory and display hardware
What it does not cover
Try in this order
0 of 4 completedCapture the exact failure state
ReversibleNote the exact update version, accessory or backup date, and confirm the feature worked immediately before it. Expected behavior: register taps, swipes and multi-touch consistently across the display.
Isolate the component boundary
ReversibleRemove charger/case/protector for a test and draw across the full screen in a simple app. Test with the new accessory removed, or check the update's known-issues note for the exact symptom. Boundary to separate: one app and screen region versus protector, moisture, accessory and display hardware.
Correct only the proven cause
ReversibleRestart/update or replace the proven accessory; service fixed dead zones. Reset the one setting the update changed, or replace the incompatible accessory.
Verify and stop safely
ReversibleConfirm normal operation with the change present for one full day of typical use. Stop for a lifted display, swelling, cracks, heat or liquid exposure.
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