Possible faulty LAN port on Axon (single Ethernet): carrier=1 but no packets pass

General
1

Board: Vicharak Axon (RK3588), single Ethernet port
Interface: end1 (no end0)
OS / kernel: <add uname -a output>
Image:

Summary

The LAN port shows a valid link, but no packets pass. The board has no other network path.

  • carrier=1
  • Speed 1000 Mb/s, full duplex
  • Port LEDs blink
  • TX packets increases
  • RX packets stays 0
  • No IPv4 address. DHCP gets no lease.
  • Only an IPv6 link-local address: fe80::.../64

Tests

  • Two different Ethernet cables.
  • Two different peers: a Mac and a site router.
  • Static IPv4 on three subnets:
    • 192.168.77.2/24
    • 192.168.2.10/24
    • 192.168.29.240/24
  • Ping to each gateway fails with Destination Host Unreachable.
  • Peer counters: Ipkts 0, Opkts > 1700.
  • No ARP reply from the board.
  • ip -br link shows only end1.

Reproduction

cat /sys/class/net/end1/carrier
cat /sys/class/net/end1/operstate
ethtool end1
ip -br link
ip -4 addr show end1
dmesg | grep -iE "end1|stmmac|phy|link is"
Question
- Is this a known PHY or magnetics fault on the Axon?
- Does the board need an RMA?
- Which additional tests do you recommend?
The port worked until 2026-10-18. The board then went offline and has not passed traffic since.
2

Our Findings

Board: Vicharak Axon (RK3588)
OS: Ubuntu 24.04.3 LTS
Kernel: 6.1.75-axon (package 20261005-axon, installed 2026-10-08)
Ethernet: single port, end1 (rk_gmac-dwmac fe1c0000.ethernet, RTL8211F PHY)

Symptom

The built-in LAN port links at 1 Gbps, full duplex, but passes no RX traffic. DHCP gets no lease and the interface gets no IPv4 address.

Evidence

Check Result
carrier 1
operstate up
Speed / duplex 1000 Mb/s / full
Autonegotiation on
Link detected yes
ethtool -S end1 TX frames 111
ethtool -S end1 RX frames 36
ethtool -S end1 RX CRC errors 36
Kernel RX packets 0
Kernel TX packets 41
TX errors 0

Every received frame fails the CRC check. The kernel receives no packets.

Device tree

The running DTB and the pre-failure backup are byte-identical for the Ethernet node:

phy-mode        = rgmii-rxid
status          = okay
tx_delay        = 67
rx_delay        = 0
reset-delays-us = 0 20000 100000
end0 does not exist. The second GMAC, ethernet@fe1b0000, is status = disabled.
Tests performed
- Two different Ethernet cables.
- Two different peers: a macOS host and a site router.
- Warm reboot.
- Static IPv4 on three subnets.
- USB Ethernet adapter on the same board.
The USB adapter works normally: DHCP, internet, Tailscale, and MQTT. The OS network stack is healthy.
Timeline
- 2026-10-08: kernel 20261005-axon installed. The port worked after this.
- 2026-10-18: the box went offline.
- 2026-10-20: the box returned online through a USB Ethernet adapter. The built-in port still shows 100% RX CRC errors.