Nighthawk M6 Pro Ethernet port

I’ve been experiencing what looks like the exact same Ethernet issue on my M6 Pro after the most recent firmware update, and I wanted to share the troubleshooting I’ve done so far.

Setup:

• M6 Pro running on AC power (battery removed, sitting on an active cooling fan)
• Ethernet set to 1000BASE-T (also tested 2.5GBASE-T)
• Devices tested: Windows desktop, Raspberry Pi, and a small unmanaged switch

Symptoms:

• Ethernet works fine right after reboot
• After >3 minutes, the Ethernet port drops completely
• No IP address from DHCP, and even with a static IP I can’t ping the hotspot’s gateway (192.168.1.1)
• Devices disappear from the M6 dashboard when the drop occurs
• Only way to restore connectivity is to reboot the hotspot, but the cycle repeats

Troubleshooting already tried:

• Factory reset of the M6 Pro → no change
• Direct connection (no switch) → same issue
• Tested with both desktop and Raspberry Pi individually → same issue
• Forced Ethernet speed to 1000BASE-T instead of 2.5GBASE-T → no change
• Tried static IP configuration → no change
• Cooling + running with battery → no change
• Cooling + running without battery → no change

At this point it looks like the Ethernet interface itself is crashing at the firmware level, not just DHCP or NAT. The timing (always a few minutes after boot) makes it feel like a firmware regression introduced in the latest update.

Is this a known issue with the latest firmware?

Is there a way to roll back to the prior firmware build, which didn’t have this problem?

Any other workarounds besides relying on Wi-Fi?