MT-6000 PPPOE connection fails

We are behind a FTTH 200 mbit conntection, using PPOE. After rebooting the router and the fibre modem, somehow, the router tried and tried to establish the PPPOE connection and fails again and again. This is what I see in the logs:

2024-08-31T10:25:44+01:00 GL-MT6000 kmwan: config json str={ "op": 3, "data": { "cells": [ "wan" ] } }
2024-08-31T10:25:44+01:00 GL-MT6000 ddns-scripts[8865]: ddns: PID '8865' started at 2024-08-31 10:25
2024-08-31T10:25:44+01:00 GL-MT6000 ddns-scripts[8865]: ddns: Service section disabled! - TERMINATE
2024-08-31T10:25:44+01:00 GL-MT6000 ddns-scripts[8868]: glddns: PID '8868' started at 2024-08-31 10:25
2024-08-31T10:25:44+01:00 GL-MT6000 ddns-scripts[8865]: ddns: PID '8865' exit WITH ERROR '1' at 2024-08-31 10:25
2024-08-31T10:25:44+01:00 GL-MT6000 ddns-scripts[8868]: glddns: NO valid IP found
2024-08-31T10:25:46+01:00 GL-MT6000 kernel: [ 1014.030724] mtk_soc_eth 15100000.ethernet **eth1: Link is Up - 1Gbps/Full - flow control off**
2024-08-31T10:25:46+01:00 GL-MT6000 kernel: [ 1014.039005] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
2024-08-31T10:25:46+01:00 GL-MT6000 netifd: Network device 'eth1' link is up
2024-08-31T10:25:46+01:00 GL-MT6000 netifd: VLAN 'eth1.7' link is up
2024-08-31T10:25:46+01:00 GL-MT6000 netifd: Interface 'wan' has link connectivity
2024-08-31T10:25:46+01:00 GL-MT6000 netifd: Interface 'wan' is setting up now
2024-08-31T10:25:47+01:00 GL-MT6000 avahi-daemon[4334]: Joining mDNS multicast group on interface eth1.IPv6 with address fe80::9c98:78ff:fee5:4e7a.
2024-08-31T10:25:47+01:00 GL-MT6000 avahi-daemon[4334]: New relevant interface eth1.IPv6 for mDNS.
2024-08-31T10:25:47+01:00 GL-MT6000 avahi-daemon[4334]: Registering new address record for *::*:* on eth1.*.
2024-08-31T10:25:48+01:00 GL-MT6000 ddns-scripts[8868]: glddns: cURL Error: '6'
2024-08-31T10:25:48+01:00 GL-MT6000 ddns-scripts[8868]: glddns: Transfer failed - retry 1/0 in 60 seconds
2024-08-31T10:25:49+01:00 GL-MT6000 **root: mtk-sdk eth halted detected, now reset it...**
2024-08-31T10:25:49+01:00 GL-MT6000 kernel: [ 1017.692883] mtk_soc_eth 15100000.ethernet **eth1: Link is Down**
2024-08-31T10:25:49+01:00 GL-MT6000 avahi-daemon[4334]: Interface eth1.IPv6 no longer relevant for mDNS.

I see this repeating itself over and over. The only way so far I have found to make the connection from being dropped is going into the Internet settings and clicking "save". Before that, I had an Archer C7 router with OpenWRT which never showed any such behaviour. Is this a hardware/driver issue? If so, why does the step I described above solve it?

What firmware version are you using?

Did you try the 4.6.3-op24-ReleaseCandidate?
https://dl.gl-inet.com/router/mt6000/

Does it work on the other wan port?

Also this is weird:

What happen if you replug the cable does it crash?

What firmware version are you using?

The current stable version. OpenWrt 21.02-SNAPSHOT r15812+1075-46b6ee7ffc / LuCI openwrt-21.02 branch git-22.335.71649-0ecaf74

Did you try the 4.6.3-op24-ReleaseCandidate?

No. How stable is it?

No. Even worse as the workaround doesn't work either. I also tried /etc/init.d/network restart, but that doesn't help either.

I get the same error. Until I apply that workaround, that is, that is until I go to Ethernet 1/Modify and then click "apply" (without actually changing anything).

Hello everyone.
This is my first post here...

Are there any news on this "user.notice root: mtk-sdk eth halted detected, now reset it..." issue ?

I think I'm experiencing quite the same with my MT-6000.
It works ok for a variable time period, I'd say 1 to 8 days maximum from when I power it on, and then it randomly looses wan connection.
When it happens, it is no more able to connect to internet, the LED blinks forever, I must power off and back on the Flint.2 to restore wan link.
If I power off/on the ONT, it doesn't fix.

I'm in Italy, my setup is brand new:
FTTH 1000/300 (ISP: Navigabene on Fibercop) ----- ONT Sercomm FG1000R ------- Flint.2

No LAN devices attached, only wifi used at the moment, just for a simple gateway device for the heating system (few bytes/s traffic).
No VPN, no AdGuard.
DDNS and Goodcloud used and working as long as wan link is ok, obviously.

Same issue with fw 4.6.2 and 4.6.4 (present version), with IPv6 off or on.
Yesterday I replaced the ethernet cable with a new one, very short and well shielded, let's see, but I don't think this is the point.

Any advice would be helpful.... thanks!

Log (also with the annoying "illegal BA buffer size" error):

Wed Sep 25 00:42:15 2024 kern.err kernel: [553302.515415] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:18 2024 kern.err kernel: [553304.563568] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:19 2024 kern.err kernel: [553306.509141] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:20 2024 user.notice root: mtk-sdk eth halted detected, now reset it...
Wed Sep 25 00:42:20 2024 kern.info kernel: [553307.470861] mtk_soc_eth 15100000.ethernet eth1: Link is Down
Wed Sep 25 00:42:21 2024 daemon.info avahi-daemon[5417]: Interface eth1.IPv6 no longer relevant for mDNS.
Wed Sep 25 00:42:21 2024 daemon.info avahi-daemon[5417]: Leaving mDNS multicast group on interface eth1.IPv6 with address ****::****:****:****:c84b.
Wed Sep 25 00:42:21 2024 daemon.notice netifd: Network device 'eth1' link is down
Wed Sep 25 00:42:21 2024 daemon.notice netifd: VLAN 'eth1.100' link is down
Wed Sep 25 00:42:21 2024 daemon.notice netifd: Interface 'wan' has link connectivity loss
Wed Sep 25 00:42:21 2024 daemon.info avahi-daemon[5417]: Withdrawing address record for ****::****:****:****:c84b on eth1.
Wed Sep 25 00:42:21 2024 daemon.info avahi-daemon[5417]: Interface eth1.100.IPv6 no longer relevant for mDNS.
Wed Sep 25 00:42:21 2024 daemon.info avahi-daemon[5417]: Leaving mDNS multicast group on interface eth1.100.IPv6 with address ****::****:****:****:c84b.
Wed Sep 25 00:42:21 2024 daemon.info avahi-daemon[5417]: Withdrawing address record for ****::****:****:****:c84b on eth1.100.
Wed Sep 25 00:42:21 2024 daemon.notice netifd: Interface 'wan' is now down
Wed Sep 25 00:42:21 2024 daemon.notice netifd: Interface 'wan' is disabled
Wed Sep 25 00:42:21 2024 kern.info kernel: [553307.901471] mtk_soc_eth 15100000.ethernet eth1: PHY [mdio-bus:01] driver [RTL8221B-VB-CG 2.5Gbps PHY]
Wed Sep 25 00:42:21 2024 kern.info kernel: [553307.911152] mtk_soc_eth 15100000.ethernet eth1: configuring for phy/1000base-x link mode
Wed Sep 25 00:42:21 2024 daemon.notice netifd: Interface 'wan' is enabled
Wed Sep 25 00:42:21 2024 user.notice firewall: Reloading firewall due to ifdown of wan ()
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 user.warn : skip line without '=' Default
Wed Sep 25 00:42:21 2024 user.warn : skip line without '='
Wed Sep 25 00:42:21 2024 authpriv.notice sudo:     root : PWD=/ ; USER=root ; GROUP=nonevpn ; COMMAND=/usr/lib/gl_ddns/dynamic_dns_updater.sh -- stop
Wed Sep 25 00:42:21 2024 user.notice kmwan: config json str={ "op": 3, "data": { "cells": [ "wan" ] } }
Wed Sep 25 00:42:21 2024 kern.err kernel: [553308.557058] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:24 2024 kern.info kernel: [553311.318750] mtk_soc_eth 15100000.ethernet eth1: Link is Up - 2.5Gbps/Full - flow control off
Wed Sep 25 00:42:24 2024 kern.info kernel: [553311.327728] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
Wed Sep 25 00:42:24 2024 daemon.notice netifd: Network device 'eth1' link is up
Wed Sep 25 00:42:24 2024 kern.info kernel: [553311.334355] IPv6: ADDRCONF(NETDEV_CHANGE): eth1.100: link becomes ready
Wed Sep 25 00:42:24 2024 daemon.notice netifd: VLAN 'eth1.100' link is up
Wed Sep 25 00:42:24 2024 daemon.notice netifd: Interface 'wan' has link connectivity
Wed Sep 25 00:42:24 2024 daemon.notice netifd: Interface 'wan' is setting up now
Wed Sep 25 00:42:25 2024 kern.err kernel: [553311.634568] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:25 2024 daemon.info avahi-daemon[5417]: Joining mDNS multicast group on interface eth1.IPv6 with address ****::****:****:****:c84b.
Wed Sep 25 00:42:25 2024 daemon.info avahi-daemon[5417]: New relevant interface eth1.IPv6 for mDNS.
Wed Sep 25 00:42:25 2024 daemon.info avahi-daemon[5417]: Registering new address record for ****::****:****:****:c84b on eth1.*.
Wed Sep 25 00:42:26 2024 daemon.info avahi-daemon[5417]: Joining mDNS multicast group on interface eth1.100.IPv6 with address ****::****:****:****:c84b.
Wed Sep 25 00:42:26 2024 daemon.info avahi-daemon[5417]: New relevant interface eth1.100.IPv6 for mDNS.
Wed Sep 25 00:42:26 2024 daemon.info avahi-daemon[5417]: Registering new address record for ****::****:****:****:c84b on eth1.100.*.
Wed Sep 25 00:42:26 2024 authpriv.notice sudo:     root : PWD=/ ; USER=root ; GROUP=nonevpn ; COMMAND=/usr/lib/gl_ddns/dynamic_dns_updater.sh -- start
Wed Sep 25 00:42:27 2024 kern.err kernel: [553313.677934] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:29 2024 kern.err kernel: [553315.724945] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0
Wed Sep 25 00:42:31 2024 kern.err kernel: [553317.772932] 7986@C14L1,PeerAddBARspActionSanity() 259: illegal BA buffer size = 0

With the new cable, tonight at 4 am it disconnected again.
I don't live in that house yet, so I lose connection from outside until I go there and reboot the router.

I read of compatibility issues of WAN port at 2.5Gb/s, could it be the case?
Is there any known fix?

For the compatibility issue of the 2.5G interface (two-way device), it is a hardware negotiation issue.

You can try to use LAN2 (ETH3) as the WAN port.