Reading further on the web I discovered that model v4 (W) comes with the possibility, by default, of uploading config file by tftp server. Maybe it is possible to update firmware by the same way....

Aprilcoco wrote Did you download the firmware of V4 and update it? Yes, V4! I took I picture of the label of the router: there's a (W) close to the model version: it means something? I didn't find in...

Model : TL-WR840n Hardware Version : v4 Firmware Version : ISP : Hi to all! I tried several times, from several differente O. S. and browser to upgrade the firmware. Always the same answer: error...