Fix to random reboots and 4G?

I have seen in the forums that 4G casuses random reboots. I am experiencing this issue. I can just set internet to 3G and random reboots disappear. However, I WANT to use 4G. What should I do? Should I contact support? I am using latest image from LineageOS (I think 15.1).

If you want to contact Fairphone support, you would have to install Fairphone OS or Fairphone Open OS and confirm the problem with either of these OSes supported by Fairphone.

LineageOS is not supported by Fairphone, but by the LineageOS community.
And the latest LineageOS build for the Fairphone 2 is 16.0 (Android 9 Pie). There are nightly builds which can be found here …

If you are indeed still running LineageOS 15.1, here’s the upgrade guide …

Also, please install the latest #modemfiles and check whether the problem persists.


Yep, LineageOS 16.0, sorry. I’ll try the latest modem files…

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I suppose most of the so called “Random Reboots” are actually triggered by pressing the power button for more than 10 seconds inadvertently, when carried in a trouser pocket e.g.

The “Power Button Reboot” is a general Android feature to be able to restart frozen phones with non-removable batteries.

I tried to avoid the accidental reboot by shortening the power button by some tenths of a millimeter.

This is how it looks originally:

This is how it is now:

It´s nearly flush with the housing, still no problem to press it with the fingertip, but nearly impossible to be triggered by chance.

Up to now I never had “Random Reboots” again!


I have these reboots with 4G since I got a new slim cover (before that it was the old cover), but I’m sure I’m not touching the power button, because even with the phone simply lying on a table or the window sill these reboots happen, and they vanish with disabled 4G.
This happens even with the newest modem files, as I’m using FP Open OS 19.5.02.

I just bought a new battery and will do new 4G tests soon, maybe 4G causes peaks in power usage and the old battery (3 years old!) was no longer able to provide enough power? Or the bloated old battery in combination with the new case caused slightly bad contacts with the SIM card? (I’m using dual SIM, but only one of the cards supports 4G)

The last modem files did the trick!
I have some reboot from time to time, but it’s because of the battery. The little legs in the bottom part broke after a fall. But with a piece of paper I hardly ever get reboots.

Also the power button sometimes does cause the reboot, but not very usually…Anyway it is a very good idea that of @PhotoPhil !! How did you managed to do it?

At first I removed the button from the black frame prying the little transparent rubber latches over the mushroom shaped pins.

Then I sanded it down with medium grit (240 or so) grinding paper. It´s a little bit tricky to keep it parallel. Reassemble, job done!

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