If an S21 Ultra misses touches or shows a colored line, the panel is five years old and the software is frozen. Samsung has ended software support for the S21 series, with One UI 7 as the last update, so a touch bug no longer has a patch coming. Test on a bare screen with the *#0*# touch grid, remove a thick protector and try a different charger. A line is a panel fault; Samsung's US list shows $229 for an S21 Ultra screen-only repair and $269 for the module with a new battery.
Differential
Likely causes of “Samsung Galaxy S21 family screen or touch input is not working correctly”, and how to tell them apart
- 1
A worn or failing panel
What separates it A line, dead patches or touches that miss in one area
How to confirm Run the touch grid; if it fails on a bare screen the panel needs replacing
- 2
A protector with an air gap
What separates it Edges miss touches
How to confirm Remove it and test
- 3
Moisture or a bad charger
What separates it Touches misfire while charging
How to confirm Dry the screen and use a Samsung charger
- 4
A software bug with no patch
What separates it It started after the last update
How to confirm Support has ended, so a factory reset is the last software step
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether there is a line or only missed touches
- The touch grid result
- Whether it happens while charging
- Whether a protector is fitted
Try in this order
0 of 4 completedRemove the protector
ReversibleTake it off and wipe the screen dry.
Run the touch grid
ReversibleDial *#0*# in the Phone app, tap Touch and trace the grid.
Try Safe mode
ReversibleRestart in Safe mode to rule out an app.
Get a repair quote
ReversibleAsk for the screen-only price and compare it with replacing the phone.
Model-specific
What is true of this model and not of its siblings
- Screen
- A 6.8 inch 120Hz display with Gorilla Glass Victus.
- A five-year-old screen
- A Galaxy S21 Ultra from 2021 has a display that has aged; Samsung's US service list shows about $229 for the screen alone and $269 for the module with a new battery, so weigh that against a replacement phone.
- Charging noise
- If touches misfire only while plugged in, a cheap charger or cable is the usual cause; charge on a Samsung charger and cable to rule it out.
- Other models this page answers
- These steps also fit the Galaxy S21+, Galaxy S21.
Stop boundary
When this stops being a self-service repair
- !If the grid fails on a bare screen, book a screen repair and compare the price with a replacement phone
- !If the screen is cracked, stop using it
Evidence ledger
Sources behind this answer
Charger, accessibility, gestures, moisture, updates, Safe mode and diagnostics.
One UI 7 as the last update.
Samsung's suggested US screen and screen module prices by model.
S21 battery, charging, chip by region, storage, Wi-Fi, display, glass and back panel.
Exact questions
Common questions
Will an update fix the S21 Ultra touch bug?+
No update is coming. Android Headlines reports One UI 7 was the last update for the S21 series.
How much is an S21 Ultra screen repair?+
Samsung's US list shows $229 for screen-only and $269 for the module with a new battery; prices vary by store.
Why does the middle of my Galaxy S21 Ultra screen not register touches?+
Owners describe a dead zone in the middle of the screen. Take off the protector, run the touch test in Samsung Members and update; a dead zone that stays on a bare screen is a digitizer fault for Samsung service.
Is a green line on a Galaxy S21 Ultra fixable?+
Not with software. A line that appears without a drop is a failing display connection or panel, and a screen replacement is the repair.
How do I run the touch screen test on an S21 Ultra?+
Open Samsung Members, Support, Phone diagnostics, Touch screen, or dial *#0*# and tap Touch to trace the grid.