Samsung Galaxy S21: Known Problems

Some Galaxy S21 screens develop a green line, which reports tie to software updates. In April 2024, Samsung India offered a one-time free screen replacement for affected phones, the S21 series included except the FE, within 3 years of purchase and even out of warranty. Samsung hadn't said whether other regions would get the same offer.

After the first Android 12 (One UI 4.0) update, US Galaxy S21, S21+ and S21 Ultra phones dropped to a 60Hz refresh rate as soon as your finger left the screen, which made scrolling and animations look jittery. Samsung acknowledged it, and SamMobile says many users confirmed a second One UI 4.0 build largely solved it, though the changelog didn't mention it. Global models weren't affected.

Samsung lists the S21 series among its IP68 phones, but says water resistance isn't permanent and can decrease over time with wear or damage. It says to keep the phone away from saltwater, pool water, soapy water and chemicals.