yup, any eeprom action / flashing comes with its own risks
if this path does not work for you and something goes wrong don’t blame me 
I’m just saying the path works if all goes well within the normal risks involving flashing
i can also upgrade;
but after reading this all, i’ll skip. I’ve got issues upgrading before with z-wave. It’s an expensive piece of sh*t actually that Z-wave. Range sucks, sometimes unavailable. Issues with Qubino smartswitch with kw/h (last bug was it got stuck at 457kwh or something).
No, z-wave vs zigbee? zigbee please!
It totally is. What you do is get a second stick. Restore to it, then upgrade. If that fails you still have your original stick.