samsung hidden test menu:
- Open Phone app.
- Type #0#.
- choose a test, like Red, Green, Blue for screen checks, Touch for touchscreen, Sensor for proximity and other sensors.
To leave a test, press back. Some tests require pressing back twice. It's very useful for spotting burn-in on AMOLED screens or a broken speaker. Some carrier variants don't support it. im about to throw this thing out the window lol

