Hello!

I’m experiencing random micro-disconnections on my Archer AX5400. The connection drops for a few seconds and then comes back, several times a day.

While checking the system logs, I noticed entries that suggest the router is switching to 3G/4G backup mode, even though I’m only using a wired WAN connection and no 3G/4G modem is connected.

Here are some of the relevant log entries:

2026-01-28 14:30:56 3G4G DEBUG [21130] backup: switch network to WIRED.
2026-01-28 14:30:41 Led Controller INFO [1676] Start to run WAN1_ON
2026-01-28 14:30:41 Led Controller INFO [1676] Start to run WAN0_OFF
2026-01-28 14:30:41 Led Controller INFO [1676] Start to run LAN_ON
2026-01-28 14:30:10 Led Controller INFO [1676] Start to run WAN1_OFF
2026-01-28 14:30:10 Led Controller INFO [1676] Start to run WAN0_ON
2026-01-28 14:30:10 Led Controller INFO [1676] Start to run LAN_ON

It looks like the router is toggling between WAN interfaces and briefly entering a 3G/4G backup or failover state, which may be causing these micro-cuts.

My questions are:

1. Why is the router activating 3G/4G backup mode when no mobile modem is connected?
2. Is there a way to completely disable 3G/4G / backup WAN / failover behavior on the Archer AX5400?
3. Could this behavior be a firmware bug, and if so, is there a recommended firmware version to fix it?

Any guidance on how to prevent these WAN switches or stabilize the connection would be greatly appreciated.

Thank you in advance.