Just want to share some experience with my watch.
Nine days ago I woke up and my watch (system software ver. 25.00) was in the infamous restart loop with the flashing triangle and in some loops reached the Garmin logo screen.
Worth to mention that this is a refurbished device that I received two years ago under warranty after my original had the exact same issue.
I plugged it into the charger, still looping. After a few hours I plugged it out and the loop continued.
All of a sudden I noticed that it had loaded and everything looked fine. Put it on and after just 15 minutes it restarted again and stuck in the loop. Took it off and after a while it loaded successfully.
Without putting it on I performed a factory reset, went through that process and put it on. 15-30 minutes later it started to loop again. This went on for some days on my winter holiday going downhill skiing and I noticed it worked fine when I was out in the slopes but went crazy going in.
I started to think that the battery was bad and ordered a replacement battery which I replaced on day seven with this issue.
First start with new battery, same thing. Put the watch in the fridge for 5 minutes and it started, warmed it up in may hands and it restarted. Tried this several times.
Went through several factory resets, ran Garmin Express updates with the watch placed in the fridge so it wouldn’t restart, only the maps updated since I was on the latest version.
Still restarting when getting warm…
Downgraded the system software to 24.10 and the 24.71 beta but still the same issue. Would restart loop when put on the radiator and load successfully when put in the fridge.
Since above didn’t help I updated to system software 25.00 through Garmin Express and placed an order on a Garmin Epix.
After the final update, when restarting the watch it gave the also infamous “Unable to authenticate maps” message. Followed the recommended action to force reinstall the maps through Garmin Express and the message disappeared.
Now to the spooky part, after that map reinstall it hasn’t restarted once in two days. I even put it in the oven in 130 degrees Fahrenheit for 30 minutes, still no restart, works as clockwork.
Regrets my Epix order since the F5X still is a pretty great device.
I know this really makes no sense but it actually happened. Bottom line with this post, don’t give up on your old device and ad odd it may seem, make sure to reinstall even updated maps and give it a bit of time. Maybe your scrapped drawer Fenix will work fine charging it up and turning it on again.