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Flashing Failures

Solutions for firmware flashing issues.

Serial Port Permission Denied​

Error​

Error: [Errno 13] could not open port /dev/ttyUSB0: 
[Errno 13] Permission denied: '/dev/ttyUSB0'

Solution​

Temporary fix:

sudo chmod 777 /dev/ttyUSB0

Permanent fix:

sudo usermod -aG dialout $USER
sudo reboot

Device Not Found​

Error​

Error: could not open port /dev/ttyUSB0: 
[Errno 2] No such file or directory

Solutions​

  1. Check USB Connection

    lsusb
    dmesg | tail -20

  2. Try Different USB Port

    • Use USB 2.0 port if available
    • Try direct connection (no hub)

  3. Check Drivers

    # Should show FTDI/CP2102 device
    lsusb | grep -i "Future\|Silicon\|Qinheng"

Flashing Timeout/Hang​

Symptoms​

  • Command hangs indefinitely
  • No progress output
  • Must Ctrl+C to stop

Solutions​

  1. Close Serial Terminals

    sudo pkill picocom
    sudo pkill minicom
    sudo pkill screen

  2. Verify Recovery Mode

    • SW1.1 = ON
    • SW1.2 = OFF
    • Power cycle board

  3. Check Power

    • Stable 5V supply
    • Adequate current (3A)

Checksum Mismatch​

Error​

Verification failed
Checksum mismatch

Solutions​

  1. Re-download Files

    • Corrupted download
    • Use different network

  2. Verify Files

    md5sum prebuilt/sbc/*.bin
    # Compare with expected checksums

  3. Try Different SD Card

    • For SD-based recovery

Flashing Succeeds but Won't Boot​

Symptoms​

  • Flash reports success
  • Board doesn't boot normally
  • U-Boot errors

Solutions​

  1. Verify Normal Boot Mode

    • SW1.1 = OFF
    • SW1.2 = OFF

  2. Check Serial Output

    picocom /dev/ttyUSB0 -b 115200

  3. Re-flash

    • Try recovery mode again
    • Use different firmware version

Quick Reference​

IssueCommand
Check permissionsls -la /dev/ttyUSB*
Add to dialoutsudo usermod -aG dialout $USER
Kill terminalssudo pkill picocom
Check USBlsusb && dmesg | grep tty
Verify switchCheck SW1 position