[Nexus 5 Original Android Development] olejonbj:
Yes, I just found that thread by googling Nexus 5 and the obviously incorrect MAC address, and in my case it is most likely overheating which affects all LG phones from the Nexus 5 era (which the firmware should take care of, turning it off, like iOS, modern laptops etc, and I know Android devices do it as well, but the overheating sensor is probably not close enough to the Wi-Fi chip).

Two possible causes in my case, see list below, but I think I can exclude the first one. I recently moved to a sub-tropical island. Pretty much the same thing happened to my HTC Desire here (the phone that really kicked off Android as a good platform). When I turned GPS on it rebooted. Found solution here, wrote a letter with a link and just gave to phone to a random store that sells HTC phones in Norway, and they replaced the motherboard (for free, it was 3-4 years old) as the thread here said was the only solution, and it was back in business and never overheated, even on the beach in direct sunlight (yeah I was testing it, knowing I could get another free repair, but after the repair the overheating sensors worked and forced the phone off until it was cooled down, so it was a hardware flaw). I thought those times were over...

Downloading large files over Wi-Fi or lots of data in a short period of time (this I think I can rule out because I could easily download OpenGapps Aroma in Norway (pretty big file) with Chrome with the phone, and here the temperature inside is just a little higher. I'm used to to sub-tropical climate so my apartment in Norway is always warm, but at the same time, here, when downloading large files, Chrome downloaded fine on Wi-Fi until a point, then just said "Download pending" and I had to cancel it and downloaded with my laptop and used adb to push the file via USB to the phone instead, so it could be)

General overheating. I always maintain my phone out of direct sunlight, if it is in a pocket in a backpack I always make sure that part is in the shadow, but at the same time I can not say that there has not been any situacion where it may have happened, and it's black and everything, like entering a really warm car before the air conditiong start working properly. I have noticed random reboots lately, also some in Norway shortly before leaving (thought it was a temporary LineageOS nightly bug or me accidentally pressing the power button for 10+ seconds in the pocket). If it was overheating it should turn itself off and deny me to turn it back on before being cooled down. So maybe the sensor work but instead of forcing cool down it reboots,

could be a LineageOS bug?

I think the post can help me fix it myself. I managed to open the cover today, never done that before. Thought it was more difficult but it is really easy. Just need to buy some really small screwdrivers that I don't have here now. Even opening the phone or making one or more humidity sensors go off does NOT break the 5 years warranty by law in Norway. The repair company then have to prove that it's the cause. A photo can be enough (opening the phone and clearly seeing water damage to the part that is not working), or a video showing that when replacing the part close to visible humidity damage it works again.

Anyway, if I can't fix it myself I will flash it to stock ROM, just to not having to claim my rights (flashing custom does not break warranty either, it's your phone and you can do whatever you want with the software, the device should handle overheating etc gracefully), and send it to repair in Norway.

Luckily I bought it in fall of 2013 so it is still under warranty until fall of 2018. It's always helpful to send a link to XDA to the repair company with the phone, because they know this forum well and if everyone says the solution is X than they do that, in this case replacing the motherboard. If they don't have it or can't order it in, they have to give me a new phone like a Nexus 5X or something.

I have had a suspicion that companies make devices last longer when sold in Norway, and it's pretty solid, because I and family and friends have had the same devices and they have broken just a few months after turning 5 years old, from phones to printers and monitors, while on Reddit the same devices break after just 1 or 2 years with the exact same error depending on the country and it's warranty time. Of course, sometimes it does not work, and it breaks some time between 4 and 5 years. As you know this is called planned obsolescence, and having worked for a big state IT department I've seend the 5 year+ thing a lot, even though if you buy as a company the 5 year warranty does not count, only for consumers, so it's 1-2 years depending on the device. But the devices are the same for the whole market, so typically we see 5 years, including a common washing machine for a building (lasted 5 years+ even though bought by the building which is officially a "company").

If I manage to fix it I will tell what I did.

Thanks so far.

BTW my MacBook Air 2013 with best CPU selected etc gets really warm (fan spinning like crazy) when compiling heavy software etc, and over long periods of time, but never has it turned off or rebooted or showed any warning of overheating even playing some heavy game for hours (I more or less never play games, but sometimes), fan like crazy, keyboard gets hot etc. My usual workstation is much much faster, Linux-based but stationary, several monitors, only CPU/PSU fans actually (it's enough), so I have never used my MacBook as heavily as now, it has always been quiet, it really needs heavy duty work to turn the fan on (that one can hear at least).