The first thing I noticed was that the touch digitizer becomes completely unresponsive if the phone is laid on certain surfaces (specially my bed and my desk). Touching the metal frame of the phone fixes this issue until I let go.
Then I noticed some ghost touches happening around the center of the screen.
I’ve been doing some hobby work with tiny electronics in the past, and this specific issue has occurred to me before in a bit of a “lab setup” where I didn’t ground the touch digitizer correctly.
I haven’t opened up my phone just yet in case this is a known issue with a known (potentially software?) fix and I’d rather avoid ripping some delicate ribbon cable or something in the process.
Does anyone have an idea? Any known solutions?
Or should I just go ahead, check the connectors or maybe do some probing to figure this out myself?
I’m doubtful. The display is all built by DJN. It communicates via i2c and SPI on a flex cable to the main board. The touch is done within the LCD cells and a chip controls both mounted on a flex PCB inside the backside of the display.
The issue with sensitivity I believe did not appear until Fairphone pushed a mitigation that reduced the sensitivity of the screen. This mitigation reduces the length of a ghost touch spaz out and maybe frequency but did not solve the issue. In my experience it’s a bad mitigation as it doesn’t solve the issue and also makes the screen way less usable.
I would get rid of the FP4 and buy a FP5 if you really want to use their products.
It’s not really the sensitivity that’s the issue, the sensitivity is actually fine Imo. I’m on a custom ROM though so I don’t know if that fix is applied there.
The “issue” is complete unresponsiveness when laid on certain surfaces that are well isolated from earth.
It’s not really an issue for me, I just pick up the phone and then it works but it’s certainly interesting and I’d like to know more.
The “sensitivity” issue solved by attaching a cable (no need to charge) or touching the frame with a finger, was introduced by the software " fix" for the ghost touches. Whatever they did, we dont know and they dont explain this or if there is any intention to fix the new bug. Maybe the CustomROM developer can explain what they did and what is causing this? Because yes the ghost touch “fix” is implemented in CustomROM as far as I know.
yvmuell’s post explains better what I was getting at. What you are complaining about is a side effect of the software mitigation that fairphone implemented.
I don’t actually think the custom ROM I am using actually has the ghost touch “fix” applied at all: I am definitely experiencing ghost touches from time to time.
Hi,
I have a 6GB variant Fairphone 4 and it’s totally fine and works really well. However, recently I got a chance to get an 8GB variant and I discovered a very weird issue that apparently is known and common based on my quick search here. When I don’t touch any part of the device, touch is unresponsive and very erratic. Touch only works well when I touch any part of the device aside from the screen. In another thread, they said that it’s possible caused by a bad workaround by Fairphone for ghost touches. However, I didn’t see any solution there or workaround. Anyone knows a solution on this?
I know it’s not a big deal but could still be annoying especially when mounted while driving I would imagine. Now I don’t know if I’ll proceed to migrate my data to from my old FP4 or not…this is a big bummer honestly
To not duplicate this further I opened one of the older topics and merged it and no there is no “solution” other than touching the phone or attaching a cable (no need to charge)
Is it hardware or software? My old one doesn’t have it so maybe they did something with the newer units? Or perhaps I can reflash an older Android version and they won’t have this issue? Or perhaps put the screen from my old one to the new one?
I dont think downgrading is a good solution as you will have to stick to the outdated software version forever. It comes with data loss as unlocking the bootloader causes a factory reset. Also you will not be able to relock the bootloader. Also the chance to face Ghost touches will increase.
Actually downgrading wouldn’t be much of an issue because I’m using Ubuntu Touch which requires Android 11 anyway. I already tried an older Android 11 (FP4-FP4G-factory) but still the same. I already have this file and I can’t find how to download older ones. Since it also exists in Ubuntu Touch, I would guess it’s the display firmware or something? I guess my last resort would be to try interchanging the screens
