Upgrading firmware on Ubiquiti (UBNT) devices is a critical step for maintaining network security and stability . While version

is often associated with specific legacy or industrial-grade firmware branches, the process for downloading and updating remains consistent across most AirOS and UniFi platforms. Where to Download Official Firmware

To avoid security risks, always download firmware directly from Ubiquiti's Official Download Page Find Your Device

: Search by model (e.g., NanoStation, Rocket, or UniFi AP) to ensure you get the exact version for your hardware. Release Notes : Check the Ubiquiti Community Releases

page for the latest changelogs, including bug fixes for connectivity and roaming. Releasebot Methods for Upgrading Your Firmware

Depending on your device's current state, you can choose from three main upgrade paths: 1. Web UI (Standard Method)

This is the easiest way for devices that are currently functional and accessible: Log into the interface. Navigate to the section, click and select the file you downloaded. Wait 3–7 minutes for the process to complete; do power off the device. 4Gon Solutions 2. UniFi Network Application

For managed environments, you can push updates through the controller: Settings > Control Plane > Updates You can also use the UniFi Advanced Updating Technique

to paste a direct firmware URL into the device's property panel. Ubiquiti Help Center 3. TFTP Recovery (Emergency Method) Software Downloads - Ubiquiti

Download Instructions

⚠️ WARNING: Do not download firmware from third-party "mirrors" or unverified file hosting sites. Ubiquiti devices are frequent targets for malware (such as the SkidMap Trojan) hidden inside fake firmware files. Always download from official sources.

Official Download Methods:

  1. Via Ubiquiti Official Website:

    • Go to ui.com/download.
    • Enter your device model (e.g., "NanoStation 5AC").
    • Look for the "airOS" firmware section.
    • Locate version 1.255 (or the closest current stable version if 1.255 is end-of-life).

  2. Via Device Interface (Easiest Method):

    • Log in to the device via IP address.
    • Go to the System tab.
    • Click "Check for Updates."
    • If the update is available for your specific hardware revision, click "Download & Install."

5. Post-Upgrade Validation

After reboot:

  • Check firmware version
    Web UI: System info panel
    CLI: cat /etc/version or uname -a

  • Verify configuration persistence – ensure custom settings remain.

  • Test basic functions – connectivity, radio performance (if wireless).

  • Review logs for errors:
    logread (OpenWrt-based) or show log (EdgeOS)

Q1: Can I downgrade from version 1.255 to an older version?

A: Yes, but not always directly. Ubiquiti includes a squashfs filesystem that may prevent downgrading across major kernel changes. Use the TFTP method and an older UPD file, but be aware that downgrading can cause factory default loss.

Common Issues After Upgrading to 1.255 & How to Fix Them

Even a smooth upgrade can introduce unexpected behavior. Here are the top three post-upgrade issues and their fixes.

8. References

Alternative: CLI Download

cd /tmp
wget https://dl.ui.com/firmware/[product]/[firmware-file].bin

Security Warning: Legacy Firmware Risks

Version 1.255 is end-of-life. The last update for this branch was around 2018. Using it exposes devices to:

  • Known CVE exploits (e.g., CVE-2018-15128 – authentication bypass).
  • Vulnerable SSL/TLS libraries.
  • No support for WPA3.

Recommendation: If you don’t need v1.255 for interoperability with old hardware, upgrade to the last available AirOS v6.x or move to AirOS 8 (for M-series devices). However, some WISPs keep v1.255 for proprietary AirMax timing.