You can find the latest firmware for V2 here: http://www.tp-link.com/en/download/TL-WA850RE_V2.html#Firmware

Hi Davews, you may send a feedback to TP-link support at support.uk@tp-link.com. Maybe they can help to develop a beta firmware.

What's your VR400's hardware version? My VR400 V2 is fine. You may upgrade the firmware to the latest one. If it is V1 with the latest firmware, you can send an feedback to TP-Link support at...

Is it identified with signal strength? You may follow the steps below: Insert a suited SIM/UIM card into the 3G/4G USBmodem correctly. Plug your 3G/4G USB modem directly into your PC anddisable the...

Oh, sorry for my mistake. I don't think there is way to configure wireless router mode as backup.

Yeah, you can do that.