ASUS RT-AC66U rev.B1 AsusWrt-Merlin Firmware 386.1 Beta 4

The AsusWrt-Merlin firmware was developed with the primary goal of boosting the original ASUS firmware, fix bugs and also add new improvements. This package includes a customized firmware targeted at ASUS routers that brings various changes without modifying the interface of the original firmware.

System:

- Various bugfixes and optimizations
- Some components were updated to newer versions, for improved stability and security
- User scripts that run on specific events
- Cron jobs
- Ability to customize the config files used by the router services
- Ability to turn off router LEDs
- Entware easy setup script (alternative to Optware - the two are mutually exclusive)
- SNMP support (except for HND devices)
- Nano text editor (for more user-friendly script editing)
- NTP daemon, which can synchronize your client devices

Disk sharing:

- Enable/disable the use of shorter share names
- NFS sharing (through webui)
- Allow or disable WAN access to the FTP server
- TLS support for the FTP server

Networking:

- Force acting as a Master Browser
- Act as a WINS server
- SSHD support for key-based authentication
- Allows tweaking TCP/UDP connection tracking timeouts
- CIFS client support (for mounting remote SMB share on the router)
- User-defined options for WAN DHCP queries (required by some ISPs)
- Advanced OpenVPN client and server support
- Support for new OpenVPN 2.4 features like NCP and LZ4
- Netfilter ipset module, for efficient blacklist implementation
- Configurable min/max UPNP ports
- DNS-based Filtering, can be applied globally or per client
- Custom DDNS (through user script or custom config file)
- TOR support, individual client control (based on experimental code from Asus)
- Policy routing for the OpenVPN client (based on source or destination IPs), sometimes referred to as "selective routing")
- DNSSEC support
- fq_codel queue discipline for Traditional QoS
- Full cone NAT support (HND devices only)
- Detailed wireless troubleshooting information (HND devices only)
- Modern DDNS client (In-a-Dyn), with HTTPS support
- DNS-over-TLS
- Redirect NTP client queries to the router's own NTP daemon
- WS-Discovery support (alternative to SMBv1 network discovery)

Web interface:

- Performance improvements
- Optionally save traffic stats to disk (USB or JFFS partition)
- Enhanced traffic monitoring with graphical reports of historical data
- Traffic report per IP (except on HND devices)
- Hostname field on the DHCP reservation page
- System information summary page
- Wifi icon reports the state of all radios
- Wireless site survey
- Advanced Wireless client list display, including automated refresh
- Redesigned layout of the various System Log sections
- Editable fields for some pages
- Advanced traffic classification report

Installation

- Simply flash it like any regular update. You should not need to reset to factory defaults (see note below for exceptions). You can revert back to an original Asus firmware at any time just by flashing a firmware downloaded from Asus's website.
- If the firmware upgrade fails, try rebooting your router to free up sufficient memory, without any USB disk plugged in, then try flashing it again.
- If you run into any issue after an upgrade and you haven't done so,try doing a factory default reset as well.
- Always read the changelog, as mandatory resets will be mentionned there when they are necessary.
- In all of these cases, do NOT load a saved copy of your settings! This would be the same thing as NOT resetting at all, as you will simply re-enter any invalid setting you wanted to get rid of. Make sure to create a new backup of your settings after reconfiguring.

NOTE:

- Resetting to factory default after flashing is strongly recommended for the following cases: Updating from a firmware version that is more than 3 releases older or Switching from a Tomato/DD-WRT/OpenWRT firmware

Installation Notes:

- This custom firmware can be applied like any regular update.
- You should not need to reset to factory defaults.
- You can revert back to an original ASUS firmware at any time.
- Do not load a saved copy of your settings.  

About Router Firmware:

Before you consider downloading this firmware, go to the system information page of the router and make sure that the currently installed version isn't either newer or matching this release.

Due to the large variety of router models and different methods for upgrading the device, it is highly recommended that you read and, above all, understand the installation steps before you apply the new firmware, even if you are a power user.

In theory, these steps shouldn't be much of a hassle for anyone, because manufacturers try to make them as easy as possible, even if they don't always succeed. Basically, you must upload the new firmware to the router through its administration page and allow it to upgrade.

If you install a new version, you can expect increased security levels, different vulnerability issues to be resolved, improved overall performance and transfer speeds, enhanced compatibility with other devices, added support for newly developed technologies, as well as several other changes.

If you're looking for certain safety measures, remember that it would be best if you perform the upload using an Ethernet cable rather than a wireless connection, which can be interrupted easily. Also, make sure you don't power off the router or use its buttons during the installation, if you wish avoid any malfunctions.

If this firmware meets your current needs, get the desired version and apply it to your router unit; if not, check with our website as often as possible so that you don't miss the update that will improve your device.