Hello everyone, I would like to report a reproducible WAN stability issue on the GL-MT6000 (Flint 2) when used with a TIM FTTH ONT in Italy. The problem appears to be related to the 2.5G WAN PHY and the MediaTek Ethernet driver under load.
I should point out that I used AI to describe the more technical parts.
Hardware involved
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Router: GL.iNet GL-MT6000 (Flint 2)
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Firmware: 4.8.4
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ONT: TIM FTTH GPON
- WAN port: 2.5 Gbps capable
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Connection type: PPPoE (TIM Italia)
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Speed profile: 1 Gbps download / 300 Mbps upload
Issue description
When the Flint 2 negotiates 2.5 Gbps on the WAN port with the TIM ONT, the router becomes unstable under medium or high traffic load. The WAN interface suddenly stops working and the following error appears in the system log:
Code:
mtk-eth: halted detected
After this message:
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the WAN link becomes completely unresponsive
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PPPoE disconnects
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link renegotiation does not occur
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the WAN interface cannot recover
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only a full power cycle of the router restores connectivity
A simple interface restart does not fix the issue.
Additional observations
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Forcing 1 Gbps via software does not work:
Code:
ethtool -s eth1 speed 1000 duplex full autoneg offThe command is accepted by the driver, but the external 2.5G PHY ignores the forced speed and continues to negotiate 2.5 Gbps with the ONT.
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AI suggests that using an external Gigabit switch (e.g., TP-Link MS105GS or LS1005G) between the ONT and the Flint 2 forces the link to 1 Gbps and completely eliminates the problem.
This strongly suggests a driver or PHY stability issue at 2.5 Gbps with this specific ONT model.
Questions:
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Is this a known issue with certain ONT models (e.g., TIM Italy GPON ONTs)?
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Is it possible to add a firmware option to force 1 Gbps WAN negotiation, if supported by the PHY?
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Are there any patches, beta firmware, or workarounds you recommend?
Thank you for your support.
Luca