I have recently identified an issue that causes the IPv6 connection to fail or stall within the hardware acceleration engine (PPE) of the MediaTek Filogic processor in the Flint 4 router—specifically when using an SFP+ XGS-PON module with a PPPoE connection configuration. So far, I have only observed this problem when the connection is established via the 10 Gb SFP+ module (everything appears to work correctly when using the 10 Gb Ethernet port).
The issue stems from the fact that, when handling IPv6 traffic encapsulated over PPPoE, the hardware acceleration engine incorrectly calculates or drops packets that exceed a certain size, which causes both download and upload speeds to be cut in half.
After conducting several tests, I managed to find a temporary workaround by manually configuring certain parameters on the router via the LuCI console—specifically, by adjusting and limiting the MTU value to bypass this hardware restriction. This allows for full wire-speed processing without any packet corruption. (I would be happy to share these settings if anyone else is experiencing the same issue.)
I have also submitted a report to GL.iNet to see if their technical department can reproduce the fault and provide a fix. Given that the router has only recently hit the market and there have been very few firmware updates since its launch, I expect this might take some time. Therefore, I would like to know if anyone else has encountered or noticed this same problem and found a similar solution. by this way we could provide more information to GL.iNet, which might help them arrive at a definitive fix more quickly.
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This post will remain open in case other users wish to share additional suggestions.
I’ve just replied to your colleagues with the information they requested. I started this thread specifically for this reason—to see if anyone else has encountered this issue and might be able to provide additional details that I may have overlooked.
As an extra detail that might be helpful: I just tested version 4.11.0 Beta4—which includes the Mesh feature to see how it performs. It seems the issue with IPv6 and acceleration doesn't occur here; however, I’ve discovered another significant bug. When using the "Private DNS" option in the main console, making any changes whether in the general DNS tab or the Private DNS tab causes the router’s configuration to become corrupted.
I tested this in two ways: by updating to version 4.11.0 and carrying over my previous configuration, and by setting up the router from scratch. In both cases, as soon as any DNS parameter is modifiedespecially regarding security DNS settings internet access breaks completely; either pages won't load at all, or they load extremely slowly. Even after resetting DNS options to its default settings, the issue persists. Once the router’s configuration is corrupted, there’s no way to restore previous settings. I’m not sure if this bug has already been reported, but it’s similar to the IPv6 issue in the previous version: once the error occurs, there’s no way to revert to a working state.