Background

For many years I have used consumer network routers that I have flashed with OpenWrt firmware. Honestly most of the time It’s a small project setting up the devices how I’ve wanted them and then basically left them alone. Over the years I have used OpenWrt on the following devices:

  • NetGear WNDR3700 (alive on another network)
  • Western Digital My Net N750 (dead)
  • Linksys WRT1900AC (v1) (retired)
  • ASUS RT-AX53U (in service)

I have seen comments to the effect that the Linksys E8450 / Belkin RT3200 are currently the best available WiFi 6 routers that are OpenWrt-supported, but I am not aware of any retailers in Australia for these devices, and I’m not yet willing to try to import any and deal with shipping costs and getting AU power bricks. Occasionally the RT-AX53U goes on special on Amazon AU for under $100, so so far I’ve bought two. Originally the second was intended to be a backup device should I have had any issues with the first device through normal use (unlikely) or when configuring or upgrading firmware (the typical cause of me bricking routers).

Installation

The OpenWrt Table of Hardware has a fairly straight-forward guide for installing OpenWrt on the RT-AX53U. I followed the process for installation with mtd-write without incident. I would recommend using the firmware selector in order to determine which factory image to install.

There have been a few issues with the configuration that has shipped with the various OpenWrt firmwares for the RT-AX52U:

  • On older firmware I had issues connecting to the internet. This I resolved by backing up config from my old WRT1900AC and restoring onto the RT-AX53U. I do not believe that this is an issue in the latest firmware release.
  • More recently when I had to unbrick my second RT-AX53U I had issues with getting the 5GHz radio working with factory settings. Looking at the differences in "/etc/config/wireless" I had to manually add "option band '5g'" and "option channel '153'" to "config wifi-device radio1".

If required follow other guides for setting up the wireless access points. Please note that some devices do not or will not support WPA3. I have run into this with some flavours of Raspberry Pi, which I have not been motivated enough to try to solve yet.

Bricking

This weekend I bricked the second RT-AX53U when trying to configure it as a dumb AP for the purposes of it being a mesh node. How I did this was that I had got to the point of there only being a LAN interface and I had set it to DHCP mode in a (very incorrect) attempt to resolve the inability to download packages. I found myself unable to connect to the device any more to change the configuration, so then I set about trying to unbrick it.

Unbricking

My initial attempts to unbrick the router were to attempt to follow the installation with TFTP instructions. I have used a similar process to previously unbrick the WRT1900AC on multiple occasions. This involved opening up the router and connecting to the JTAG using a PL2303 (Prolific USB to Serial) cable. Unlike the WRT1900AC there are no pins on the RT-AX53U JTAG which makes it fiddly as. Windows 10/11 ships with deliberately broken drivers for the PL2303. I was able to find a copy of an older working driver on a D-Link support page. Annoyingly updating the driver requires a restart, and whenever you plug in the cable it defaults to the newer nonfunctional driver. Also running the tFTP server software for downloading the firmware image to the router has connections blocked by windows firewall. After I spend quite some time hitting these issues in various combinations I was able to get the router to download the firmware successfully only for the flashing to fail.

Next I attempted to follow the ASUS Rescue Mode instructions. I got through the whole process only for the final status to indicate that there was an error flashing the firmware. Later with the JTAG connected I saw that on booting the router detected that there was an issue with the firmware in the flash and that it then restored from the other partition. Then I was back to factory firmware running but with a password I could not remember.

First I attempted to restore to factory settings by following the reset to factory settings instructions. This did not work. Then I located these Hard Factory Reset instructions which did work. Then I successfully followed the instructions to install OpenWrt.