@THECATTO Use MR600 user guide - Chapter 4.2 to locate the NAT option - it should be in Advanced > Network > Internet. You should disable the MR600 LAN DHCP server as well - Chapter 11.4.2. Finally,...

@azgar Yes, that's the procedure, just like upgrading the FW, but with an older version. You're doing it just right. Some FW releases can't be downgraded and this is stated in the release notes. For...

@azgar I am using Archer C64 without any issue so far, but with FW 1.11.30. I noticed that you're on the latest FW version - 1.12.0. Can you downgrade to the previous version 1.11.30 and check if...

@mrwogu Well, let's try something else then - create a configuration backup of your C80 (from its WebGUI and also take some notes aside, just in case you can't use this configuration file later). If...

@mrwogu Check this post - @iAmSaugata have managed to downgrade from beta FW to v1.11.30 Build 220624 Rel.50807n(5553). Try that and check if this solves the issue.

@mrwogu Try the beta FW from this thread and check if this fixes your issue.