after some hours of trying,
i just found out easy way to flash meshtastic on twatch S3 by Web-flasher.
if flashing does not work:
open back cover, careful flip out the battery, you will find very small button under that.
connect USB, prepare webflasher, press and hold small button, press crown for 1 second. let both go.
start flashing from webflasher.
this did work for me meshtastic 2.2.2
have fun
BTW: the backside cover of the watch is saying T-watch-2020 which is not the model i ordered, but chip_id output below…
ESP32-S3 so its just the older housing of 2020 model
:
C:>python -m esptool chip_id
esptool.py v4.6.2
Found 1 serial ports
Serial port COM5
Connecting…
Detecting chip type… ESP32-S3
Chip is ESP32-S3 (revision v0.2)
Features: WiFi, BLE
Crystal is 40MHz
MAC: 48:27:e2:e9:bf:9c
Uploading stub…
Running stub…
Stub running…
Warning: ESP32-S3 has no Chip ID. Reading MAC instead.
MAC: 48:27:e2:e9:bf:9c
Hard resetting via RTS pin…
Thanks for the tip! Worked. Any tips on what specific settings work with the watch? I tried double-tap, color screen etc… Also, would be nice to have a large time display, just cause it’s a watch…
yes, time display would be nice. what version did you flash?
i have not upgraded yet.
I flashed 2.2.19 because it fixes the screen flip. It was driving me nuts that it was upside down. So far it’s quite awesome to have Meshtastic on your wrist. I’m noob. This is my second device and I can finally see messages as I can’t connect to anyone where I live. Now have to figure out all the battery saving tricks, mine dies in hours (but that’s because I fidget with it). It gets very weird when people ask me what time it is. I don’t know. Well look at your smart watch! Yeah, about that…
yee, also on mine : battery is just good for a few hours… its not a consumer product, but nice to have 
Took mine for a drive today. I like that it can get location from the phone and report it to the network. Was kinda sad there is no GPS chip in the watch but this works.
One thing I believe will make the battery last a tad longer is if there is a way to stop the screen from constantly waking up on shake (accelerometer). Through the entire car ride this thing was mostly on. 45 minutes later ran out of battery lol.
Also, if I disconnect it from the phone app, will the Bluetooth circuit go to sleep and conserve some battery? Does it even consume much energy? I guess I’ll find out on my ride back home. Commuting to/from work suddenly became less boring.