In some older Samsung phones, especially the Galaxy S21 series, a thin green line appears on the displays. The exact cause is unclear, but it could be a hardware defect that can be exacerbated by overheating after a software update.
There are many reports online of display issues occurring on some older Samsung Galaxy devices. The problem manifests itself as a thin vertical green line and primarily affects the Galaxy S21 series phones, with the Galaxy S21 Ultra and S21 FE models being most frequently mentioned.
Some users associate it with software updates or heavy use in games The exact cause of the green line problem remains unclear. Software-related crashes are usually resolved by a simple reboot or factory reset. The fact that the problem persists for some users suggests a potential hardware defect.
The most likely cause of the green line problem is a faulty display connector or flex cable. These internal components connect the display to the main board of the phone and any damage or loosening of them can cause the display to malfunction.
A quick search on social media platforms shows that many users have experienced similar issues with their old Samsung models. Most of the cases were related to software updates. While Samsung has yet to officially acknowledge the issue, the company has offered repairs and replacements for similar issues that users of the Galaxy S20 series have experienced in the past.