Troubleshooting

Field-tested fixes for the most common ALPON X4 issues. Each entry lists the observable symptom, the probable cause, and the minimal fix. Work through the sections in order when bringing up a device for the first time: power, then LEDs and boot, then connectivity, then GPIO and peripherals, then the operating system.

Power and Boot Issues

The ALPON X4 accepts three independent power inputs: USB-C PD, 9 to 30 V DC terminal block, and optional PoE+ on PoE-variant SKUs. All three share a common rail through hardware ideal diodes, so the device always draws from the source with the highest voltage. Typical consumption is 7 to 14 W, with a 27 W peak under full load.

LED States and What They Mean

The ALPON X4 surfaces device health on four front-panel LEDs: Power, Connection Status, Cellular Status, and a Programmable RGB. Reading these indicators is the fastest first diagnostic when shell access is not yet available.

What does each LED pattern indicate?

Connectivity Issues

The ALPON X4 has four network paths: LTE Cat 4, dual-band Wi-Fi, 1 Gbps Ethernet (ETH/G), and 100 Mbps Ethernet (ETH). When more than one path is available, the ALPON Cloud agent handles failover in priority order. Most connectivity problems reduce to antenna torque, eSIM profile state, or link priority.

GPIO and USB Issues

The GPIO Add-on port is an RJ45 connector exposing six configurable CM4 GPIO pins (SPI5, UART4, UART0, I2C2, I2C3) at 3.3 V logic, plus a 5 V / 1 A power output gated by GPIO 21. The two USB 2.0 ports share a 1 A combined current budget.

# Enable the GPIO Add-on 5 V rail and check for fault
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(21, GPIO.OUT)   # ADDON_PWS_EN
GPIO.setup(20, GPIO.IN)    # ADDON_PWS_FAULT

GPIO.output(21, GPIO.HIGH) # Enable the rail

if GPIO.input(20) == GPIO.LOW:
    print("Fault: overcurrent, overtemperature, or reverse voltage")
else:
    print("Add-on rail enabled, 5 V available on Pin 8")

ALPON X4 OS and SSH Issues

The ALPON X4 ships with ALPON X4 OS, a Sixfab-customized 64-bit Raspberry Pi OS Lite (Bookworm) image with the Sixfab Connect agent, ModemManager, Docker, OpenSSH, mDNS, and the hardware watchdog daemon pre-installed. The default user is alpon with password sixfab; the hostname follows the format alpon-<MAC>.

# Two reliable ways to reach the device
ssh alpon@alpon-<MAC>.local      # mDNS, requires same VLAN
ssh alpon@<DEVICE_IP>           # Direct, works across routed subnets

# Default password: sixfab, change before production
sudo passwd alpon

ALPON Cloud and Container Issues

ALPON Cloud (connect.sixfab.com) handles device registration, fleet health monitoring, browser-based remote terminal access, container deployment, OTA updates, eSIM profile management, and network failover. The on-device agent (sixfab-connect) is pre-installed in the ALPON X4 OS image.

Before You Contact Support

Running through these checks covers more than 90% of field issues and gives Sixfab support the context needed for a fast resolution.

Collecting a support bundle

# Single-shot bundle you can attach to a support ticket
sudo journalctl -b -n 2000 > ~/alpon-x4-journal.log
dmesg > ~/alpon-x4-dmesg.log
vcgencmd get_throttled > ~/alpon-x4-power.log
mmcli -m 0 > ~/alpon-x4-modem.log
cat /etc/os-release > ~/alpon-x4-os.log
tar czf ~/alpon-x4-support.tar.gz ~/alpon-x4-*.log
# Attach ~/alpon-x4-support.tar.gz to your Sixfab support request.

Get Support

If the issue persists after working through this guide, reach out with the support bundle and the LED state you observe.

Where to Next