I disabled the pin completely as a workaround so the phone is instantly re-connecting to the mobile network. But since others are having this problem too (phew), i hope for a bugfix.
Yep… I’m quite happy, that it doesnt seem to be a defect of my fairphone. Mine was switched off for two weeks now, because I had to wait for a new display. I’m quite fed up with defects right now.
Thanks for sharing your workaround @chmod775 . It is so simple, that I don’t know why I didn’t have this Idea 
Got the same problem for 2 days now. sometimes just emergency calls allowed, then pin is requested again and cellular working for a while.Sometimes I have to turn the sim slot off and on again or rebooting the phone. Tried it in slot 1 and 2
I’m experiencing the same problem since yesterday. At random times, I need te re-enter my sim pin. I have a belgian SIM which never caused any problems.
Same problem here, started two days ago. FP2 all over sudden asks for the SIM PIN.
Hey chmod,
Unfortunately it is not possible to undo the update to OS 1.5.1
After this update, my SIM-card is locked randomly (reinsert didn’t help)
Removal of the Pin makes at worthwile to steel the SIM 
Regards, Kees
Same problem here. However, it started today and I installed 1.5.1 once it was out - so quite some time ago. I seriously hope this does not mean that the Fairphone is killing my SIM again, see FP2 kills some SIM cards
The Fairphone killing SIM issue was supposed to be fixed, plus the symptoms where different, so I would assume that is not the problem.
Thanks. However, notice that it does not seem to be related to the update to 1.5.1. Also it does not seem to be related to the GPS as I do Pokemon Go a lot and it has started a lot later. So I think being afraid of the SIM degenerating as a reason is not that surprising.
Nice to see that it helps you! Was my last chance not to be offline randomly 
I can confirm that this issue is also happening with a fresh sim-card, and my old one is not destroyed like the other problem / bug. I think this one is a totally different issue.
Meeeh, i know. But nobody knows that i dont have a pin Just joking - yes, its a weak consolation. But in my case much better than a randomly offline phone. But as i said, its just a workaround -not a lifetime-solution.
Hi,
It’s the same with my FP2. Starting yesterday evening (a few days after updating to 1.5.1) I have to enter the PIN randomly. Reboot doesn’t help. Both SIMs (T-Mobile Germany) worked perfectly fine until then. Has anyone asked for or got any feedback from support on this topic?
Kind regards,
Andreas
Calling in with the exact same issue. Started one or two days ago, have to re-enter the pin 1-4 times a day.
Vodafone card and OS 1.5.1.
Probably somehow related to changes that came in with the update.
Same Problem with one of my two FP2’s
SIMs are:
Slot1: Vodafone Germany
Slot: T-Mobile Germany
Has anyone contacted support team for this?
Same issue.
Started today whereas I have my FP2 since January…
I use Location Service heavily since beginning of July (yes, for Pokémon GO…) and I had no issue with my SIM PIN until today.
Tried reboots of the FP2, reinsterting the SIM but no results.
EDIT: I am still on OS 1.4.2 so does not seem linked to 1.5.1
Did you try the options listed in this support article?
Otherwise as a temporary workaround you could disable the PIN Code from SIM card and use PIN Code from the Phone itself, as Fairphone suggests in this tweet:
I have an assumption: The problem could be caused by a defective GMS update. According to the reports, it’s unlikely that the problem is caused by a FPOS update, the network or the SIM card.
Can you explain this a bit more? I’m just curios. Is there an up-to-date non google os so people can compare?
Strange. I’m having the same issue with the sim card since yesterday. It started suddenly. Before that I had absolutely no problem with the phone.
Same PIN problem here since yesterday. 1 SIM card in slot1 VodafoneNL.
Together with the over active display makes the Fairphone almost unusable.
Contacted support by phone today 6 times. Either busy ringtone, endless music or a recorded voice telling that all support people are busy. It is not easy being green and fair. FixIT Fairphone please.
Yes, they are pretty much overworked:
Though I wonder if this is rather related to an app update, or what @TobiasF mentioned, about an GMS update. It seems pretty suspicious that the issue occurs suddenly (and not right after an FP OS update, moreover with different FP OS versions), yet around the same time for many users, and still not for all users. This makes me suspect that maybe the root cause is not connected to Fairphone/ FP OS after all.
Did anyone try to make a logcat of the problem? (I can’t, since I am not affected. Yet?)
Edit: on the other hand I don’t find this problem when searching for it online.