Didnt want to create a new thread since I am having a similar issue and tried to use the solutions from this thread, to no avail.
I got a refurbished Gear 2 Neo as gift and it was working okay. However, some apps such as heart rate didnt function. Also, I couldnt transfer music to the device and some other things, so I decided to do a factory reset on it from the settings menu. Watch has not functioned since.
I can get to the reboot menu (continue, download, recovery, shutdown). If I press continue it will show the gear 2 boot screen, then the samsung boot animation =, then black screen. If I press download, it takes me to the download option and I can flash files through odin with no errors. However, when it reboots, same black screen. If I try the recovery option, same thing.....black screen. If it is of and I plug it in, it vibrates and charges, but I cannot get it to boot past the samsung animation.
I have tried flashing a PIT file, stock FW, tizen ROM......nothing works. I got a refurb because I wanted this exact watch, but it is discontinued. I am not new to flashing. I have a rooted and flashed a Galaxy s5, my current phone Note 4 and y current tablet, a samsung Note 10.1 2014.
edit.....
http://xdaforums.com/gear-2-neo/development/android-wear-gear-2-gear-2-neo-t3182056
I flashed the ROM from this thread and my watch works........go figure. I would still like to figure out what is wrong when I flash OEM FW