airMAX - How to Reset Your Device with TFTP Firmware Recovery

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If you already tried resetting your device to factory default values with the reset button and you can't access the unit, we recommend that you perform a TFTP recovery.

This guide refers to a PC running Windows or Linux, but is easily applicable to any other operating system. You will need:
  • A narrow tool to press down reset button (like a paper clip)
  • An Ethernet cable
  • TFTP client running on PC
  • Latest airOS firmware, downloadable from the airMAX Downloads section (use the left hand menu to find the correct firmware). The firmware used is dependent on:
    1. The firmware compatible with the product, be it a M or AC model.
    2. The version (use the latest available unless otherwise recommended by UBNT). 

Table of Contents

  1. Introduction
  2. Steps: Recovery Procedure for Windows
  3. Steps: Recovery Procedure for Linux
  4. Related Articles


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By reloading fresh firmware to restore the device, this process can also be useful to recover devices that have appeared to fail when no other solution is working.

WARNING: Do not switch off, reboot or disconnect the device from the power supply during the firmware upgrade process, as these actions will damage the device!

Steps: Recovery Procedure for Windows

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  1. Power off the device.
  2. Configure your computer: Windows PC's Ethernet must be configured manually with the following settings (under Network Connections):
    IP Address:, Subnet Mask :
  3. Connect your device to the PC.
  4. Press the reset button on the device. While holding the reset button down, power the unit on. Wait 8 seconds then release the button (if you want to reset the unit to factory defaults, wait about 15 seconds or until the signal LEDs light up to indicate that the device is ready for recovery).
  5. For airCubes (ISP and AC): Push reset button and hold while powering unit. LED panel should blink fast several times, continue holding the reset button and the LED should turn off. Now you can release the reset button and the LED will flash slowly three times.
  6. Make sure that the device responds to pings (perform a ping from a DOS window), if it does not, go back to the first step and repeat.

  7. Upload firmware image file .bin to, using a TFTP client software (binary mode). Windows integrated command line TFTP client or download a third party utility to upload the airOS firmware. Below are two alternatives:
    • Method 1: From the Windows PC, you can use TFTP command line from a DOS window (START>>>CMD): 

      Go into the same directory structure as the firmware (e.g., assuming that you have stored the image files in c:\firmware directory, type the command :cd c:\firmware) and enter the following (for help type TFTP -h) , e.g.:

      tftp -i put WA.v8.5.0.36727.180118.1314.bin

    • Method 2: Download and execute tftp2 and configure it as in the image below to upgrade:

  8. Signal LEDs will keep blinking one by one in 4 different colors during firmware upgrade. Wait for about 7-10 minutes (devices and firmware depending). Remember to not power off the device during the procedure!

Steps: Recovery Procedure for Linux

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Generic Linux distributions have an integrated command line TFTP client. From a PC running Linux, you can upload via TFTP by typing into Terminal the following commands:

tftp> bin
tftp> trace
tftp> put WA.v8.5.0.36727.180118.1314.bin
Sent 1965199 bytes in 35.2 seconds 
tftp> exit

Related Articles

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airMAX - Choosing the Correct Firmware for a M Device

airMAX - Choosing the Correct Firmware for an AC Device