OpenWRT Installation procedure for Asus RT-AX1800S (from stock firmware)

Hi there,

After many trials and errors, I want to suggest a complete procedure to install OpenWRT in Asus RT-AX1800S from stock firmware :

00-Download :
- https://www.asus.com/ca-fr/networking-iot-servers/wifi-routers/asus-wifi-routers/rt-ax1800s/helpdesk_download?model2Name=RT-AX1800S
- Latest version of the router's original firmware (to restore in the event of a problem)
- Asus “Firmware Restoration” application
- https://firmware-selector.openwrt.org
- The latest “Kernel” version of OpenWRT for the corresponding router
01-Use a Windows 11 virtual machine (new installation) and bridge the virtual machine network card to the physical ethernet network card
- You can also use VirtualBox (free)
- Download the extension package (available on the same official download page) and install it in VirtualBox.
- Add the downloaded files
- Install the Asus “Firmware Restoration” application in the virtual machine
02-Set router to rescue mode:
- https://www.asus.com/support/faq/1000814/
03-Follow the procedure by clicking here :
- https://www.linksysinfo.org/index.php?threads/the-wireless-router-is-not-in-rescue-mode-asus-rt-n66u-help.68801/page-2
- Set IP and netmask as shown (192.168.1.x/ 255.255.255.0)
- Set gateway to 192.168.1.1
- If this doesn't work, try instead (192.168.50.x/ 255.255.255.0)
- Set gateway to 192.168.50.1
- Disable Windows firewall
- In virtual machine only
- Disable other adapters in Network Connections, except LAN (ETHERNET)
- In virtual machine only
- Restart Windows
- No reboot necessary (under normal circumstances)
- Remove the cable from the router's LAN port (if connected). You can keep it in the computer
- Put the router into recovery mode by pressing Reset and switching it on. Hold down the Reset button until the power LED flashes slowly.
- Disable LAN on computer
- Re-enable LAN on computer
- Connect the cable to one of the router's LANs (not the WAN!).
- In Firmware Restoration, select the firmware you wish to install.
- Now, when you press Upload in the Firmware Restoration application, the upload of the new firmware version should succeed.
- If the upload was successful but the router no longer starts (stuck in rescue mode or boot loop):
- Perform a Hard Factory Reset:
- https://www.asus.com/ca-en/support/faq/1039077/
- Put the router back into rescue mode and repeat all the above steps, this time upload the latest version of the original firmware.
- Repeat all the above steps, this time upload the latest version of this router's OpenWRT “Kernel” firmware.
- Re-enable other adapters and Windows Firewall
04-Install the Kernel version with the “Firmware Restoration” tool
- Unable to make Openwrt 21.02.1 work on Asus RT-AC65P - #16 by Daquirm
05-Connect to the router interface (LuCI) with your web browser
- IP : 192.168.1.1

In some computers, the Firmware Restoration tool doesn't detect the router, so the virtual machine was my solution for that.

Is it 1800s or 1800s v2

It's 1800s (v1)

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It is among supported devices
https://openwrt.org/toh/asus/rt-ax54
Please tell which part of guide in wiki you ttied in what order etc:
https://openwrt.org/toh/asus/rt-ax54

the other device version - two is wip fifty-seven equivalent

The "Installation with mtd-write" ( https://openwrt.org/toh/asus/rt-ax54#installation_with_mtd-write ) part didn't work. I followed my procedure instead.

OK, story sounds credible. There have been case ax53 file transfer glitched over wifi....

  • upload factory file under shorter name to avoid typos
  • md5sum both files (there is no sha256 on OEM-WRT to compare to the web)
  • mtd-write if files match
  • make screenshot of putty or copy text before reboot if any errors are there

There were no errors after executing mtd-write. I waited some seconds for the execution to finish and then quit ssh session and rebooted the router. After that, the router was still in stock firmware.

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Downgrade factory firmware to earliest if possible (or upgrade to latest if at factory original), then repeat ritual.

That's what I did (It's in the procedure I posted earlier)

You did asus recovery, the mtd-write is much simpler, you enable SSH and copy file.

I tried that but it didn't work (in 2 routers of the same model)

Maybe somebody was there, wait 24-48h if they come around. I succeded with v22 year and some ago using mtd-write method