Firmware update: Asuswrt-Merlin 378.51

Asus uses Tomato-derived firmware called Asuswrt for its newer routers, such as the RT-N66U and RT-AC66U. This firmware is open source except for a few drivers, the binaries of which are included.

Asuswrt-merlin is a modified version of the original firmware that includes bug fixes and minor improvements, but still tries to stay close to the original, so that it remains possible to add new features that Asus introduces to the code. Version number 378.51 a new release of Asuswrt-merlin has just been released and its release notes can be found below.

Asuswrt-Merlin 378.51


  • Updated OpenSSL to 1.0.0q (no real code change)
  • Split the changelog into a separate file
  • Added logging on custom config/script execution. An error message will also be logged if those are disabled while such a file is found.
  • Allow pasting the password in some fields that would disable it (patch by gfairchild)


  • RSSI not reported for guest clients (beta 1 regression)
  • DM failing to install on RT-AC66U (beta 1 regression)

Asuswrt Merlin 378.51 Beta 1

The RT-N16 is no longer officially supported. The increased number of separate router platforms is becoming too much of a burden for one single developer, as some features must be implemented 2-3 separate times for different architectures. The RT-N16 support will remain in the source code, so other developers can still compile their own builds, and possibly take over for supporting this older platform. However, no new features will be implemented, and it will no longer get tested. I still welcome external contributions if someone else wants to take care of testing and providing fixes to new issues.


  • Added support for the RT-AC3200.
  • ARM support for Entware, using Zyxmon’s Qnapware repository.
  • Redesigned Wireless Log page displaying connected wireless clients. The new page uses Ajax to automatically update itself at a user-selected frequency, for near realtime monitoring of your connected wifi clients.
  • NAT loopback can now be chosen between Disable, Asus’s original, and Merlin’s own (based on Phuzi0n’s original DD-WRT design). The option can be found on the Firewall page.


  • Reverted RT-AC66U driver to previous version as some users were experiencing stability issues with the 3754 version.
  • Updated p910nd to 0.97 to resolve incomplete print jobs (patch by stsichler)
  • Updated Samba to 3.6.25
  • The Entware setup scripts will now backup any existing installation rather than remove it (patch by TeHashX)
  • Re-implemented our original NAT loopback code, with attempts at reconfiguring it whenever the DPI engine is restarted. This is still experimental, as most of the DPI engine is closed source, so unsure if the loopback gets re-enabled in every regular DPI restart scenarios.
  • Disabled the offline default error page. Clear your offline content in your browser to fully get rid of it.
  • Removed security warnings if FTP/Samba are configured to allow unauthenticated users.


  • Issues when connecting with Russian ISPs relying on DHCP+VPN (such as Beeline)
  • When enabling WAN access to webui, the router would always forward both http and https ports regardless of if either of these were disabled.
  • Shared printers over LPRng would sometime fail to completely print the last page (patch by stsichler)
  • CVE-2015-0240 security issue in Samba 3.5.8 (used by AiCloud). The main Samba daemon was patched by the update to 3.6.25.

Version number 378.51
Release status Final
Website Asuswrt-Merlin
License type GPL