Following @Antimailer’s post below I created a poll and will move the posts from the random reboots thread here, so in case this turns out not to be of relevance these posts don’t clutter the thread.
Please first try the tips here and then vote below:
I also think that the problem is often caused by the hardware. I have noticed that inside the app Kernel Adiutor (Statistics/Vendor) my Qualcomm processor hardware is shown as MSM8974PRO-AB and if I look at the processor info of my friend’s FP2 which has problems with random reboots it is shown as MSM8974PRO-AA. By the way processor info can also be watched in Settings/About phone/Processor info.
Problems on the FP2 of my friend could be minimized by reducing CPU maximum frequency, Sync Threshold and Input Boost Frequency by one level, i.e. 1958, 1574 and 1267MHz. Additionally I observed that one core was always off (possibly misadjusted by factory?) and I activated it manually using the slider in Kernel/CPU.
But maybe this is a singular case.
Does anyone have random reboots with the “AB” processor and none of the available workarounds are useful?
What about a poll?
I have the AA version but I don’t have random reboots (I’ve had some at the beginning only).
AA and hardly any random reboots. Don’t know what the two previous phones were.
AA and reboots several times a day
AA and no random reboots so far.
MSM8974PRO-AB and It reboots often (since the installation of Hiccup done on january, FP2 had reboot 31 times) but now after last update to OS 1.13.0 it doesn’t reboot anymore 
MSM8974PRO-AB and no reboots at all.
AB and it reboots 2-3 times a day
My processor is of type AA.
I have my FP2 since February 2016. At first I had many random reboots. Mostly when the CPU was under heavy load (games, navigation,…). Using google maps navigation while driving was virtually impossible. The phone would always reboot sooner or later.
Over time it got better. I assume the software updates did the trick for me.
The biggest improvement came with
Fairphone OS version 1.10.1 - 19 December, 2016
- Fine-tuning of the voltage regulator settings for the LPDDR3 memory to ensure proper regulation in some units under certain conditions that could cause occasional crashes
[…]
I’m pretty sure my phone was affected by this issue.
My reboots always happened the same way: Freeze for a few seconds 
reboot.
Memory corruption leading to a freeze and a reset triggered by the processor’s watchdog seems a realistic explanation for this behavior.
Now the random reboots are down to an acceptable level (about 1-2 times a week). And I can use heavy load applications like google maps navigation without reboots.
Accordint to CPU-Z, I have a processor of type AB. And I had nearly no reboots in the last months.
How did you adjust processor settings ? Do you have tutorial to follow ?
These CPU settings can be set for instance with the App Kernel Adiutor (requires root).
In Kernel Adiutor open the menu, choose CPU, scroll down to the settings, change them.
It was in Antimailer post actually, I missed it …
Thanks a lot !
AA and many reboots (on average 1 per day or more).
I suggest to indicate in a more relevant form how to check the kind of processor (it took me a while to find out how to do it).
AA with many reboots BUT non only on high CPU usage.
At first with OpenOS last year the main reboot causes where due to 4G settings for SIM1 (didn’t try on SIM2 as it isn’t 4G); other causes where basically environmental ones especially on high summer temperatures.
With latest OpenOS versions reboots went more rare and mainly with high CPU usage.
No I’m on MM beta and I suffered some reboots last week during high CPU load (gaming) only and 4G problem seems to be solved because I’m on 4G for 2 months (even with OpenOS or with MM beta).
On MM I also can notice the phone becomes hot more frequent than on LP, even with normal usage (not only gaming), but the scenarios are very different because on LP I didn’t have GApps and I had also a lower battery consumption (about 2.5 days, while now it barely reaches 1.5 days).
Since yesterday I’m trying to limit the CPU frequency because while gaming the phone becomes very hot, so I’ll report back in the next days 
UPDATE: no reboots until now (up and running for 90 hours) even during gaming + battery charging (which was a frequent cause of reboots) with CPU freq limited to 1497MHz, all 4 cores active
I notice one core going offline and back by itself when I start Kernel Auditor. When I activate it manually, an other starts switching. Only after activating all of them, they seem to stay activated (but for how long?)
This is interesting. Even though there is not a mutually exclusive relation, the issue seems to be processor related (with AA processors having more reboots).
However there are still too few answers to the poll. It would be interesting to do some stats with a bigger sample!
Hi. My FP2 randomly reboots around once/week - AA processor
This is a replacement for a handset which rebooted many time each day, but I don’t know the processor.
Happy to give you more info if it might help. Just tell me what’s required.
Barry
Well, the current standings don’t look too good for AA processors, I guess I’m just lucky for the time being …
People with random reboots should perhaps try changing the processor settings as proposed by @Antimailer:
As for doing this:
It would be pretty interesting whether that helps for their processor or not.