MT6000 Flint 2 - Cable Not Detected

Mr_Inc · 2025-04-02T09:56:20.139Z

I updated to 4.7.4 in January from 4.6.? which I had had running with no issues since the start of December. Although I tried Adguard at that time I gave up for a while but started to use it again recently. I decided to update Adguard using the script from admon here.

However, I now have an issue if I soft-boot or power-cycle the router, the router cannot detect a cable on the WAN (eth1) port and refuses to connect. I have a TP lan switch connected to the WAN/LAN (Lan1) port set up as LAN and that continues to work fine as I can access the router from my PC.

When this first happened I just disconnected and reconnected the Cat cable and that appeared to solve the issues. The second time it happened this solution did not work, so I tried a new cable and attached it to the ONT (UK - Openreach box with EE Broadband 900Mbs) in place of the old one. This appeared to work.

However, on another reboot the problem resurfaced. The only way I could get the Flint2 to re-connect to the ONT was to power off both router and ONT. This never happened before the upgrade.

I have attached two logs -

After a soft-reboot when no cable detected.
After a power-cycle when no cable detected.

I have had issues sometimes with DNS when using Adguard and the sync not working, and do a soft reboot which sorts it out for a while. At the moment whilst the Internet is connected and working, I have disabled Adguard and I am not needing to schedule a reboot, which I would like to do. But if the router has an issue with connecting afterwards, this will not work for my needs.

logread_no_connection.tar (250 KB)
logread_no_connection_after_power_cycle.tar (259.5 KB)

bruce · 2025-04-03T08:18:02.959Z

Hello,

How about if other devices such as PC LANs connected to this primary router (or ISP Modem) also have such a situation?

Not sure may be the 2.5Gbps port compatibility issue, but it is not very similar.

You can change the 2.5G WAN port of Flint2 to 1Gbps mode to test, SSH to router:

ethtool -s eth1 speed 1000 duplex full

If the port is running stable, it can be saved permanently:

sed -i '/exit 0/i\ethtool -s eth1 speed 1000 duplex full' /etc/rc.local

Mr_Inc · 2025-04-03T09:10:43.314Z

The MT6000 is the only router connected to the ONT/Modem. The issue appears to be the MT6000 WAN connectivity to the ONT Modem. The PCs and wifi devices attached to MT6000 connect fine and operate fine other than no internet connectivity.

I will try changing the default speed on the WAN connection to see if that resolves any disconnect issues that I may still encounter.

mortneff · 2025-04-03T13:58:24.760Z

Mr_Inc:

When this first happened I just disconnected and reconnected the Cat cable and that appeared to solve the issues. The second time it happened this solution did not work, so I tried a new cable and attached it to the ONT (UK - Openreach box with EE Broadband 900Mbs) in place of the old one. This appeared to work.

This makes me think the issue either some issue with how the cable auto negotiates or devices or connections.

Mr_Inc · 2025-04-04T09:59:48.293Z

I suspect it was the ONT's negotiation that was getting into a knot because now that the ONT was rebooted, I no longer have an issue with 'cable not detected'. If it happens again I will try Bruce's suggestion of setting the speed of the WAN to 1Gbps from 2.5Gbps.