Here is the pin-out diagram drawing of Samsung Galaxy Watch Model SM-R800. Although all Samsung Products are coming with a USB cable connectivity with computers, so you can flash your device with firmware and reset it to factory setting. But unfortunately Samsung Watches doesn’t not come with such ability. In most of these watches user need to connect the watch by a wireless connection. And it does need a computer with wireless connectivity. Well sometimes your wireless connection might break or your watch get bricked and you will have no way to connect your watch by a wireless connection.
So here is the solution; you will have to open the watch and solder a USB wire. This Technic does need some soldering skills. So you will need to have a soldering station and other tools to open the Watch and solder the wires inside the motherboard. Although there are some connectors seen online, that does not require soldering. But they are not available at the moment.
So by this method you will connect your watch with computer and with help of Odin software. You can easily flash your watch with firmware you have. The connection may need you to download and install Samsung drivers into your computer. So your computer will recognize your watch. Be careful with colour coding of the USB wires, as some USB wires are colour coded incorrectly. So the Red wire is a positive connection and black is negative connection. The two other wires are coloured with white and green are the data transfer wires.
For this method after soldering the wires, you will need to put your watch into download mode and connect the USB wire to your computer. Your computer will recognize and install necessary drivers and odin will recognize your watch and show up the COM port in the Odin. Just load up the firmware and flash your watch.