[FIRMWARE] for UAP/USW has been released | Stable Candidate

by Ubiquiti Employee 2 weeks ago (16,978 Views)

We've prepared firmware Please see below for the changelog and links to the firmware binaries. This release is planned to only be Stable Candidate/blog release, so it will not be promoted to Stable.


Firmware changes since 4.0.21

  • [UAPG2/G3] Handle broadcast DHCP replies properly while using dynamic VLANs.
  • [UAPG1/G2] System optimizations.
  • [UAPG1] Fix Ethernet negotiation.
  • [AC-Pro/EDU/M-Pro] Fix performance regression in 4.x when uplink is 100Mbps.
  • [HD/SHD/XG/BaseStationXG] Update kernel.
  • [BaseStationXG] Fix GPS support. 
  • [nanoHD/IW-HD] Add association tracking support.
  • [nanoHD/IW-HD] Add support for `High Performance Devices` (also part of `Auto-Optimize Network`). 
  • [nanoHD/IW-HD] Add support to display which client STAs support Fast Roaming. 
  • [nanoHD/IW-HD] Enable client STA keepalive support.
  • [nanoHD/IW-HD] Fix 802.11w (PMF) provisioning. 
  • [nanoHD/IW-HD] Fix a crash when running RF Environment scanning.
  • [nanoHD/IW-HD] Fix a null pointer access issue.
  • [nanoHD/IW-HD] Fix AndesSendCmdMsg warnings (reported HERE and HERE).
  • [nanoHD/IW-HD] Fix downlink AP TX rate degradation issue.
  • [nanoHD/IW-HD] Fix some memory leaks.
  • [nanoHD/IW-HD] Fix wireless uplink packet forwarding issue.
  • [nanoHD/IW-HD] Stability improvements.
  • [UAP-IW] Fix link flapping and switch VLAN behavior.
  • [UAP-IW] Fix port/management VLAN provisioning.
  • [UAP-IW] Fix reported inittab respawn errors (reported HERE).
  • [UAP] Add DFS backup channel feature.*
  • [UAP] Add initial RFC-5176 support.*
  • [UAP] Add U-NII-2C support for Panama country code. 
  • [UAP] Fix a bug with guest portal redirection.
  • [UAP] Fix and improve User Groups support. 
  • [UAP] Fix Apple Watch support when using `Auto-Optimize Network` feature.*
  • [UAP] Fix connectivity issue for 2.4GHz only devices when using `Auto-Optimize Networks` or `High Performance Devices`.
  • [UAP] Fix false `Blocked by access control` anomalies.
  • [UAP] Fix false DHCP timeout/failure anomalies.
  • [UAP] Fix incorrect/lower than expected 2.4GHz TX power limits. 
  • [UAP] Fix issues when multiple guest networks on an AP.*
  • [UAP] Fix RADIUS failover behavior.
  • [UAP] Fix RF Environment scanning bug which caused APs to require a power cycle after running a scan (reported HERE and HERE).
  • [UAP] Improve client STA compatibility when using `High Performance Devices` (also part of `Auto-Optimize Networks`).
  • [UAP] Regulatory updates for Russia.
  • [USW-Pro/XG-6POE] Further improvements to PD autodetection.
  • [USW-Pro] Add initial routing support.*
  • [USW-Pro] Add LCM brightness/sync support.*
  • [USW] Add Wired User Experience support.*
  • [USW] Fix 10/100Mbps manual negotiation.
  • [USW] Fix false PoE overload events.
  • [USW] Fix SNMPv3 data leaking without auth.
  • [USW] Improve Fault Status text when checking PoE info via shell.
  • [SEC] Fix CVE-2019-8912.
  • [HW] Fix alerts generated when inittab restarts a process.
  • [HW] Miscellaneous bug fixes and improvements.

*controller support pending



  • You may start to see EVT_AP_RestartProc events in the controller log. If you see these, please report if there is anything specifically in your setup that triggers the events. The processes restarting is not new, but the reporting of the restarting is, and we are using these reports to clean up these issues.
  • Any US-XG-6POE upgrading from 4.0.2 or earlier will take a long time to upgrade. Don't be surprised if your switch is unavailable for 5-10+ minutes as 4.0.3+ also updates the PoE firmware to improve PD compatibility.
  • 1st gen UAPs may require extra steps when upgrading from firmware 4.0.3. You can try disabling all WLAN groups, and then running the upgrade. Devices that are seemingly "stuck" on 4.0.3 may require TFTP recovery to upgrade from that firmware.

  • All supported 1st gen APs need to be on a minimum of 4.0.10 prior to upgrading to this firmware. Controller 5.10.3+ will force an upgrade to 4.0.10 prior to upgrading to this release (only if your device isn't running 4.0.10 already).

Known Issues:

  • UAP, UAP-LR, UAP-IW, UAP-OD and UAP-OD5 cannot be downgraded from firmware 4.0.17+ to an earlier release.




*This firmware is meant to be a one file solution that works with all models of UniFi switch. You can use it when upgrading from 3.9.40+ only. It will not work when upgrading from earlier releases.


Any and all feedback is welcome, including lettings us know about successful device upgrades. When reporting an issue, please ensure that you include the following information:

  1. Controller version.
  2. Firmware version (previous and current). 
  3. Device model(s). 

Links are all HTTPS. This assumes your device(s) are currently running at least 3.7.56, and that the device's date is properly set (i.e. it can reach a NTP server). If you encounter issues with the upgrade, or your device isn't on a minimum supported firmware, then you can change the link to HTTP before performing the upgrade.