miniVNApro - Check for bootloader presence

In some cases the integrated bootloader of the miniVNApro is corrupt and so for the firmware update via vna/J is not working.

This is only relevant for the miniVNApro, not the pro2, tiny or any other modell!


LED numbers

When I refer to LED numbers, please check this picture and the table below:

 11 09 2017 10 47 50

# Color Usage



Analogue section activated.

To reduce power consumption during battery operation, the analogue section may be deactivated by the firmware.



Digital section activated.

Always lit, while the miniVNApro is connected to an active USB-port or running on battery power.



Li-Ion battery is being charged.



Data transfer from remote PC to miniVNApro



Data transfer from miniVNApro to remote PC



Bluetooth connection status

¬∑         Blinking - searching for counterpart

¬∑         Constant - connected



Bluetooth data transfer active

Verification steps

To check whether its a bootloader issue or another problem please follow these steps:

  1. Turn the miniVNApro upside down.
  2. Connect the USB port to your computer
  3. LED 4 / 5 should flicker and then are off
  4. LED 1 / 2  should be on
  5. After a second LED 1 is turned off
  6. Launch vna/J and execute a scan (reflection/transmission)
  7. LED 1 should be on and LEDs 4 / 5 should flicker
  8. After the scan LED 1 / 2 should be on
  9. Press the red button at the miniVNApro.
  10. All LEDs are off
  11. Release the red button at the miniVNApro.
  12. LED 5 should flicker and then is off
  13. LEDs 1 / 2 should be on
  14. After a second then LED 1 is turned off

The result of Step 11 is important. If LED 5 flickers right after releasing the red reset button at the vna, the booloader seems to be intact.

If the bootloader is intact, you should be able to use vna/J to update the firmware.

If not, a new bootloader has to be flashed to the miniVNApro memory. Contact mRS for further support