I had the exact same issue, my phone wouldn’t open fully. I disassembled it following some videos (there are plenty on YouTube). When I got to the hinge, I noticed not only a lot of dirt had built up, but also that the small brushes, which are supposed to clean the hinge, had come loose because the adhesive had weakened. This started clogging the hinge. There are videos where people open and close the phone in water or try to poke the brushes out with everyday objects, but I don’t recommend those methods.
I disassembled the phone and removed the brushes. If you’re careful, you can remove the display—it’s easy to lift and remove the adhesive underneath. It just takes time and patience. After that, it comes off nicely, but make sure to first remove the back cover and the external display because the inner display has ribbon cables on both sides.
Unfortunately, I rushed things a bit and tried to lift the display when the adhesive was already removed on one side but not completely on the other, which caused it to crack. However, it still worked fine afterward—just a small crack that’s visible under certain lighting conditions.
Once the inner display and the hinge are out, you can easily access the ribbon cables. It’s worth replacing them too, as they’re cheap and there are two of them in the device. These cables often break, causing display issues, Wi-Fi problems, touch issues, etc.
In the end, I had to buy a couple of ribbon cables and a new bezel because it’s tough to remove the old one without breaking it.
Good luck to anyone attempting this repair! While they say it’s unfixable, it’s not that complicated, you just need to be cautious.
Samsung Galaxy Z Fold 4 Fully Not Opening -- Hinge Repair -- QASWA TELECOM - YouTube
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