mt7925e: Cannot communicate with some peers on mesh network (ARP/L2 frames fail)

mt7925e: Cannot communicate with some peers on mesh network (ARP/L2 frames fail)

Hardware

• MediaTek MT7925 802.11be [14c3:7925] (Lenovo subsystem 17aa:e0ff)
• Driver: mt7925e
• Kernel: 6.18.6 (CachyOS)
• Firmware: linux-firmware 20260110

Network Environment

• Google Nest WiFi mesh network
• Multiple mesh nodes, both 2.4GHz and 5GHz bands

Problem

The MT7925 can connect to the WiFi network and communicate with the gateway and some peer devices, but cannot communicate with other devices on the same subnet. Specifically:

• Gateway (192.168.86.1): reachable
• Windows laptop (192.168.86.151): reachable
• 3D printer (192.168.86.27): unreachable

All devices are on the same /24 subnet. The unreachable device works fine from other clients (Windows on the same WiFi network can reach it).

Symptoms

• ARP resolution fails: ip neigh show shows FAILED for the unreachable device
• Even with a static ARP entry (ip neigh replace ... nud permanent), connection times out
• nmap -Pn shows ports as "filtered"
• curl returns "Connection timed out"

Workarounds attempted (none helped)

• Disabled power_save: iw dev wlan0 set power_save off
• Disabled ASPM: modprobe mt7925e disable_aspm=1
• Static ARP entry with correct MAC address
• Switched between 2.4GHz and 5GHz bands
• Bluetooth already rfkill'd

Diagnostic data

$ uname -a
Linux legion 6.18.6-2-cachyos #1 SMP PREEMPT_DYNAMIC Sun, 18 Jan 2026 01:31:44 +0000 x86_64 GNU/Linux

$ lspci -nnk | grep -A3 "Network controller"
82:00.0 Network controller [0280]: MEDIATEK Corp. MT7925 802.11be 160MHz 2x2 PCIe Wireless Network Adapter [Filogic 360] [14c3:7925]
	Subsystem: Lenovo Device [17aa:e0ff]
	Kernel driver in use: mt7925e
	Kernel modules: mt7925e

$ iw dev wlan0 link
Connected to e4:5e:1b:8f:fa:02 (on wlan0)
SSID: [redacted]
freq: 2462.0 (channel 11)
signal: -52 dBm

$ ip neigh show dev wlan0
192.168.86.151 lladdr 50:e0:85:f4:58:80 STALE    # Windows - works
192.168.86.27 lladdr 70:68:71:fa:db:0b PERMANENT # Printer - fails
192.168.86.1 lladdr e4:5e:1b:fe:c8:44 REACHABLE  # Gateway - works

$ ip route get 192.168.86.27
192.168.86.27 dev wlan0 src 192.168.86.32

Hypothesis

The driver cannot send/receive L2 frames to devices connected to certain mesh nodes. The reachable devices may be on the same mesh node as the MT7925, while unreachable devices are on different nodes.

The report identifies the mt7925e driver entry point but names no source file or test. Start by reproducing the ARP and L2-frame failure with the listed MT7925 hardware and mesh setup, then trace the driver behavior for peers on different mesh nodes. Done means identifying the cause and verifying peer communication without the listed workarounds.