A thin green line appears on the screens of some old Samsung phones, especially the Galaxy S21 series. The exact cause is unclear but it could be a hardware fault that could get worse due to overheating after a software update.

There are many reports on the web about display problems occurring on some older Samsung Galaxy devices. The problem manifests itself as a thin vertical green line and primarily affects phones of the Galaxy S21 series, with the Galaxy S21 Ultra and S21 FE models most mentioned.

Some users attribute this to software updates or heavy gaming usage. The exact cause of the green line problem remains unclear. Software-related crashes are usually resolved with a simple reboot or factory reset. The fact that the problem persists for some users suggests a possible hardware malfunction.

The most likely cause of the green line issue is a faulty display connector or flex cable. These internal components connect the display to the phone’s motherboard, and if they become damaged or loosened, it can cause the display to malfunction.

A quick search on social media platforms reveals that many users are experiencing similar problems with older Samsung models. Most of the cases were related to software updates. Although Samsung has not yet officially acknowledged the problem, the company has offered repairs and replacements for similar problems that Galaxy S20 series users have experienced in the past.