from the device with the back switch in OFF mode, please follow those steps:
- prepare the USB stick, formatted in FAT32 with the factory reset file
- insert the USB stick in the device
- toggle the back switch to ON (the front LED should become red)
- press the push-button on the front (the led should become green)
after a few minutes, the factory reset procedure should be completed, and you should see again the device on the network (if connected via Ethernet) and the hotspot for the first configuration should be created