[LG G Watch R] Tremulant1:
This is going to be a somewhat long thread (fair warning) because i'm going to try and give as much detail as possible. So here we go...

Disclaimer, I am not responsible for any damage to your watch if you decide to follow my method.....it worked for me

Also be advised I used this method to allow my watch to finish the boot cycle because the watch was freezing because of being on the cradle for too long and the battery getting super hot, if your watch is doing something else, this probably won't work for you.

It all started when I factory reset my watch at 15% thinking it had plenty of battery to finish the process (I know its been said many times on this thread about having 65+% battery when doing anything to your watch...I suggest you follow that rule or even just charge to 100% to make sure). So during the initial boot cycle the watch shut off. When I get home I put it on the cradle and I saw a black screen with a battery and a charging symbol on it. After that it showed the LG logo...then began the boot animation with the colored balls. After about 5-10 seconds the watch froze and turned off again. I tried everything I possibly could, keeping it on the cradle...taking it off...booting into fastboot...letting it charge.....boot into recovery....letting it charge....flashing TWRP...letting it charge....nothing would work. It ALWAYS froze and shut off. Sometimes it was during the boot cycle, sometimes inside the fastboot screen, and sometimes in recovery. I reflashed the boot/system/and even recovery images....tried different roms....nothing seemed to work.

Now here's the good news...I was able to get it to finish the boot cycle, get to the screen that said "Android starting apps" and to another screen that allowed me to actually charge the watch to 20%....and here is what I think is happening.....The cradle and/or USB connection is giving the watch enough power to turn on and keep it on...but there isn't any voltage control so its making the battery more hot than it should....thus over heating the CPU/chipboard and freezing the watch (I say this because after the watch would freeze I would have to wait a long period of time..sometimes 30 minutes...sometimes hours...before it would show me the black screen with the charging symbol again). So I asked myself...how can I keep the watch cold enough so that it doesn't overheat yet still give it enough power to finish the boot cycle? Well I ended up grabbing my icepack (it's a clay icepack with a blue cloth around it so it wasn't making direct contact to the ice pack and there was no moisture) and I ended up placing the watch on the cradle connected to the wall charger so it had enough power to turn on, see the LG Logo and I swipped from 11->5 and went into the fastboot screen. I then let it charge up for about 30 seconds, took it off the cradle and hit "start" for it to boot normally. Then I put it on the icepack for about 15 seconds (I put the bottom of the watch where the chip board is against the ice pack).....then took it off, and placed it on the cradle for 15 seconds, I repeated this over and over it allowed the battery to maintain a decent temperature and allowed the battery to charge enough to keep it on and get to the next screen that told me to charge the battery to atleast 20%. Once it got to 20% it told me to swipe to the right and it started the pairing process, once it paired and it started syncing the apps from the phone to the watch...it actually froze again because I left it on the cradle. Once I let the watch cool off I did the process over again and this time kept switching between the ice pack and the cradle until AFTER it finished syncing and I actually saw the analog watch on the screen. After that I was able to put it back on the cradle and it charged to 100% with no issues and my watch has been working perfect ever since, and I've already charged it multiple times.

I hope this helps someone else....I had my watch not working for just over and week and everyday I would try something else and this is what FINALLY fixed it. I even went as far as buying another BL-S3 battery and was going to replace it. Good luck, if anyone has any questions i'd be happy to try and answer them.

Good Luck!