@Nic21 Hi, please connect to the 4G router via either Ethernet cable or via WiFi, then login its web interface via tplinkmodem.net or 192.168.1.1(internet is not required), then send us screenshot of...

@deepakvrao Hi, MR600 and MR100 use different firmwares but the wireless router mode with 3G/4G Backup works the same way on the two models, so it is okay to set up MR600 in an identical manner.

@mk089 Hi, you could find the fimware on global site and your current firmware is the latest one: Download for Archer MR400 | TP-Link

@Zavac Hi, I've sent you a private message, please check if it helps.

@Tugrulk Hi, under 3G/4G Router mode, the LAN/WAN port will be LAN port, so you could use the Ethernet connection and WiFi at the same time. For firmware update, you could refer to this guide: How to...

@dnlahmd Please follow this guide for troubleshooting: LTE keeps disconnecting If problem still exists, please provide the required information for futher analysis.