@sunshine Thank you! I'll try again over the weekend. It seems that the Tether app really doesn't work with the RE450 (at least my RE450), so I'll try the work laptop, which does have wifi.

Hello, thank you for this, but nothing works - see my answers below your various points: 1. Please check whether Wireless password of your router you entered is correct or not? Please go to...

No idea about hardwares and firmwares, or even where to find such things. All I know is that I follow the instructions to the letter, the app tells me that it's applying my settings, it gets to 100%...