Galaxy Z Fold 4 has a serious manufacturer’s defect that Samsung refused to fix under the warranty،
After four hours of using soda can fragments to clean the hinge, the phone's owner was finally able to open the device flat. But with the hairs broken up and removed from the device, the chances of debris entering the phone and damaging the internal screen have increased. Explaining the technique he used, ahmed1smael wrote: “The seal runs along the hinge on both sides. I checked the side where the glue was coming out the most to identify the broken side. I then carefully used thin plastic and cut up pieces of soda can to search and remove the wires and the plastic gasket.”

After cleaning hair and adhesive from the Galaxy Z Fold 4 hinge, this Redditor was able to open his device flat
He says Samsung continues to deny that the adhesive used for the bristles stops working, leaving the bristles to get stuck in the hinge. It also warns Galaxy Z Fold 4 users experiencing the same issue to report the issue to Samsung's warranty instead of trying to copy what it did. “Please use the warranty, argue your case, and don’t give up,” the Redditor writes. “This is a manufacturing defect.”
Samsung does not believe the problem is their responsibility. As Rocket 3431 said on Reddit: “Yes, I have the same problem and they want to charge me for the repair. This is complete stupidity. This phone is not worth it. Countdown until it is paid and can go back to a slab. The old Note 9 In my drawer looks so tempting. Several Redditors said Samsung refused to repair its Galaxy Z Fold 4 under warranty due to accidental scratches or damage chip on the charging port which had nothing to do with the problem.