DEC840 gets stuck on boot if ax1 is linked

[feld]

OPNsense 26.1.8_5-amd64

I have Quantum Fiber for my internet service and my CPE equipment is a C5500XK. Unfortunately I don't have a GPON SFP that will let me bypass this equipment at this time.

I have a 10GBASE-T SFP+ 30m https://www.fs.com/products/111919.html

If I attempt to boot my DEC840 with this physical link up it gets stuck and fails to complete booting. I have tried replacing this SFP as I have many on hand, but they all produce the same behavior. Changing this out for an 1G transceiver works fine and it boots noticeably faster than the 10G.

I am attaching the boot log captured over serial console at boot via script+screen. I had to clean this up a bit as it had all the terminal control characters and color sequences littered throughout but I think it's fully intact.

What I have observed is that there are some additional i2c devices detected when the 10G module is used, and it seems to fail to configure/communicate with the SFP based on the timeouts it displays in the boot log.

If I boot the firewall without the physical link up (unplug ethernet), and then plug in after fully booted it works fine -- or at least I don't notice any issues with the link or its stability.


edit: I want to mention that this hardware configuration worked fine for a couple years, but I can't be certain when this problem started happening. I believe it started somewhere within the 25.x series.