Troubleshooting

This guide covers common issues encountered with the Interceptor Carrier Board and their solutions.

Power Issues

System won’t power on

Symptoms: Power LED doesn’t illuminate, no activity.

Solutions:

1. Verify ATX PSU is switched on (check rear switch)
2. Check that 24-pin ATX connector is fully seated
3. Verify PSU is functional (test with another system or PSU tester)
4. Check front panel power button wiring on J2

System powers off randomly / crashes

Symptoms: System runs for a while then shuts down or freezes.

Likely Cause: Unstable +3.3V rail from PSU.

Solutions:

1. Replace PSU - This is the most common cause. Low-quality PSUs cannot maintain 3.3V under low load conditions typical of Pi-based systems
2. Use a Flex ATX PSU from the Exaviz Store or a quality brand (Corsair, EVGA, Seasonic)
3. Check voltage with multimeter (should be 3.3V ±5%)

System unstable under load

Symptoms: Crashes when accessing SATA drives or using PoE.

Solutions:

1. Verify PSU wattage is adequate for your configuration
2. Check 12V rail capacity (especially with PoE boards)
3. Ensure all power connections are secure

See also: SATA drives dropping under sustained I/O for detailed symptoms and diagnosis when drives fail under load.

Boot Issues

Keyboard not working at boot menu

Symptoms: Keyboard works after OS loads but not in boot menu or during early boot.

Cause: Some keyboards (especially Apple keyboards) are not recognized during early boot stages.

Solution: Use a standard PC/Windows keyboard for boot menu navigation and initial setup. Your preferred keyboard can be used after the OS loads.

“GPT no bootable partition” error

This error has two common causes:

Cause 1: CM5 USB boot limitation

CM5 cannot boot from USB 2.0, and the Interceptor board only has USB 2.0 ports.

Solutions for CM5:

1. Use SD card boot - If CM5 has blank eMMC, it will boot from SD
2. Flash eMMC - Use a separate Raspberry Pi IO Board (CM4 or CM5 IO Board both work) with rpiboot to flash the OS to eMMC, then install CM5 on the Interceptor

Cause 2: Windows flashing issue

Flashing OS images from Windows can sometimes create invalid GPT partition tables that prevent booting. This affects CM4 and CM5 when booting from USB flash drives.

Solutions for Windows flashing issues:

1. Flash from Linux or macOS - This consistently resolves the issue
2. Flash to SD card or eMMC instead of USB flash drive
3. Try a different tool - Raspberry Pi Imager or Balena Etcher

See FAQ for more details.

No video output

Symptoms: HDMI displays show no signal.

Solutions:

1. Try the other HDMI port (J4 or J5)
2. Banana Pi CM4: Only HDMI0 (J4) works - this is a known limitation
3. Check config.txt for HDMI configuration issues
4. Try a different HDMI cable or monitor
5. Connect via SSH to verify system is booting

SD card not detected

Solutions:

1. Try a different SD card
2. Reformat card as FAT32 (for boot partition)
3. Re-flash the OS image
4. Check SD card slot for debris or damage

Slow boot from USB flash drive (~45 second delay)

Symptoms: System takes 45-60 seconds to boot from a USB flash drive. You see the network link activate and DHCP requests before the OS finally starts loading.

Cause: This is a boot order timing issue, not a hardware problem. The USB flash drive needs 1-2 seconds after power-on for the USB subsystem to enumerate it. The default EEPROM boot order (0xf215 or similar) tries SD → USB → Network. SD fails almost instantly (~100ms), so the bootloader reaches USB before the drive is ready. It moves on to Network boot, which takes 30-60 seconds to timeout (DHCP requests, link negotiation). After the timeout, the boot loop restarts and USB succeeds on the second pass.

You are effectively paying a ~45 second Network boot penalty because the USB drive needed an extra second or two to enumerate.

Fix: Set USB as the first boot device. The bootloader’s own initialization (EEPROM config, clock setup) provides enough time for the USB subsystem to be ready by the time it checks the first boot mode:

# CM4: Requires a Raspberry Pi IO Board + rpiboot to update EEPROM
# CM5: Can be updated from the running system
sudo rpi-eeprom-config --edit

Set:

BOOT_ORDER=0xf2614

This decodes as (right to left): USB → SD → NVMe → Network → restart.

With USB first, the drive is already enumerated when the bootloader checks it, so it boots immediately without ever reaching Network.

Network Issues

Ethernet switch not detected (RTL8367RB err=-19)

Symptoms:

• dmesg shows rtl8367rb: err=-19 or similar
• No DHCP IP address on WAN port
• Network interfaces missing

Likely Cause: Usually indicates a bad CM4 module or improper seating.

Solutions:

1. Reseat the CM4 module
2. Check CM4 connector pins for damage
3. Test the CM4 on a Raspberry Pi IO Board if available
4. Try a different CM4 module

No network connectivity

Symptoms: Cannot ping or SSH to the device.

Solutions:

1. Check Ethernet cable connections
2. Verify link LEDs on the RJ-45 ports are illuminated
3. Try a different port on J8
4. Check IP configuration:

   ip addr show
   

Only some ports working

Solutions:

1. Check individual port LEDs
2. Try different cables
3. Check switch driver is loaded:

   sudo dmesg | grep rtl
   

Storage Issues

SATA drives not detected

Symptoms: Drives not showing in lsblk.

Solutions:

1. Check SATA and power cables are connected
2. Verify drives work in another system
3. Check controller status:

   sudo dmesg | grep -i "sata\|jmb\|ahci"
   lspci | grep -i sata
   

Poor SATA performance

Symptoms: Slow transfer speeds.

Solutions:

1. Check for SATA errors:

   sudo dmesg | grep -i error
   

2. Verify AHCI mode is enabled
3. Check cable quality (use quality SATA III cables)

SATA drives dropping under sustained I/O

Symptoms:

• Drives make beeping or clicking sounds under heavy I/O (RAID rebuild, large file copies)
• Multiple SATA ports re-linking simultaneously
• Kernel logs show ATA bus error and failed command: READ FPDMA QUEUED
• Link speeds progressively degrade from 6.0 Gbps → 3.0 Gbps → 1.5 Gbps
• System load spikes (load average exceeds CPU count)

How it presents:

A single bad SATA cable causes one port to re-link repeatedly. But when multiple ports start failing at the same time — especially during sustained I/O like a RAID rebuild — the cause is almost always an undersized PSU that cannot deliver enough current on the 12V rail.

The drives momentarily lose power, causing the SATA link to drop. The kernel detects the link failure and re-establishes it at a lower speed. This cycle repeats, degrading performance further and producing audible beeping as drives spin down and back up.

How to diagnose:

1. Check how many ports are re-linking:

   # Count re-link events per port
   dmesg | grep -c "ata1: SATA link up"
   dmesg | grep -c "ata2: SATA link up"
   dmesg | grep -c "ata3: SATA link up"
   

2. Check for speed degradation and bus errors:

   # Look for speed limiting and failed commands
   dmesg | grep -E "ata[0-9]: (limiting|SATA link)"
   dmesg | grep "failed command"
   

3. If one port is re-linking → likely a bad cable (swap the cable)

4. If multiple ports are re-linking simultaneously under load → PSU cannot supply enough power

Solutions:

1. Stop any heavy I/O immediately (e.g., stop a RAID rebuild) to prevent potential data loss:

   sudo mdadm --stop /dev/md0
   

2. Upgrade your PSU. See the sizing guide below.
3. Once the PSU is replaced, reassemble and rebuild:

   sudo mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1 /dev/sdc1
   

Fan Issues

Fans running at full speed

Expected Behavior: The fan headers (M1-M4) do not support PWM speed control. Fans will always run at full speed when connected.

Workaround: Use low-noise fans or external fan controllers if noise is a concern.

Fans not spinning

Solutions:

1. Verify fans are 12V DC (not PWM-only)
2. Check fan connections
3. Test fans on another 12V source

Serial Console Issues

Cannot connect via UART

Solutions:

1. Use a 3.3V USB-to-Serial adapter (not 5V!)
2. Check TX/RX are not swapped:
   • Adapter TX → Board RX (J2 Pin 6)
   • Adapter RX → Board TX (J2 Pin 5)
   • Connect GND
3. Use correct serial settings: 115200 8N1

Video Issues

No HDMI output

Symptoms: No video on either HDMI port.

Solutions:

1. Reseat the compute module — Improperly seated modules are a common cause of HDMI issues. Power off, remove the CM4/CM5, and reinstall ensuring proper alignment on both connectors
2. Check connector pins — Pins can become damaged invisibly during installation
3. Try a different HDMI cable
4. Try the other HDMI port
5. Test on a Raspberry Pi IO Board — If available, test the CM4 on a standard Pi IO Board. If the green LED doesn’t light, the module may be defective
6. Try a known-good module — If you have another CM4/CM5, swap to verify

No display on HDMI1 (Banana Pi)

Expected: This is a known limitation. Only HDMI0 (J4) works with Banana Pi CM4.

4K resolution issues

Solutions:

1. Verify monitor and cable support HDMI 2.0
2. Check config.txt settings:

   hdmi_enable_4kp60=1
   

Getting More Help

If you’ve tried these solutions and still have issues:

1. Gather Information:

   # System info
   uname -a
   cat /etc/os-release
   
   # Hardware detection
   lsusb
   lspci
   lsblk
   
   # Recent errors
   sudo dmesg | tail -100
   

2. Contact Support:

   • Email: support@exaviz.com
   • Include system information and error messages

Next Steps

• FAQ - More common questions and solutions
• Hardware Interface - Connector reference
• Software - OS configuration and drivers
• Getting Started - Setup guide

Last modified February 25, 2026