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How to Convert a TM-AC1900 to an ASUS RT-AC68U/P

A step-by-step method for converting TM-AC1900 firmware and boot data to the ASUS RT-AC68U or RT-AC68P configuration.

By Reflash Lab Posted Updated

ASUS wireless router

This guide covers the method I use to convert a TM-AC1900 to the RT-AC68U or RT-AC68P configuration.

Tools and files

You will need WinSCP, PuTTY, a file archiver, the ASUS Restore Utility, and the conversion files referenced below.

Conversion procedure

  1. Install WinSCP, PuTTY, and a file archiver. Ninite can install all three. Also install ASUS Firmware Restoration from the official RT-AC68U support page.

  2. Create a folder named router on the desktop.

  3. Download the conversion archive and extract it into the router folder. It contains the downgrade firmware, upgrade firmware, and mtd-write.

  4. Assign the PC a static IPv4 configuration:

    IP address: 192.168.29.5
Subnet mask: 255.255.255.0
Gateway: 192.168.29.1

    In Windows, open ncpa.cpl, open the Ethernet adapter properties, then edit Internet Protocol Version 4 (TCP/IPv4).

  5. Put the router into Recovery/Restore mode. Begin with the router powered off. Hold the Reset button, turn the router on, and continue holding Reset for 10 seconds.

  6. Open http://192.168.29.1 in a browser. If the Mini-CFE page does not load, use the ASUS Restore Utility. If neither works, perform the NVRAM reset described in Step 18 and retry this step.

  7. Flash TM-AC1900_3.0.0.4_376_1703-g0ffdbba.trx.

  8. Allow up to five minutes for the router to reboot. The Wi-Fi lights turn on when booting is complete.

  9. Sign in to the router with username admin and password password.

  10. Open Administration > System, set Enable SSH to Yes, and select Apply. You can also open the direct settings page.

  11. Connect PuTTY and WinSCP to 192.168.29.1. Use SSH in PuTTY and select SCP as the file protocol in WinSCP. Depending on the firmware state, the credentials may be admin / admin or admin / password.

  12. In PuTTY, create a backup of the original CFE:

    cat /dev/mtd0 > original_cfe.bin

  13. Refresh the remote pane in WinSCP and confirm that original_cfe.bin is present.

  14. Copy original_cfe.bin to a local drive and preserve that untouched backup.

  15. Upload original_cfe.bin to the CFE editor. Select 1.0.2.0 US AiMesh as the source CFE, download the generated file, and rename it new_cfe.bin.

  16. Upload new_cfe.bin, mtd-write, and FW_RT_AC68U_30043763626.trx to the router with WinSCP.

  17. In PuTTY, run:

    chmod u+x mtd-write
./mtd-write new_cfe.bin boot
mtd-write2 FW_RT_AC68U_30043763626.trx linux

  18. Perform an NVRAM reset, then allow up to five minutes for the router to reboot:

    1. Power off the router.
    2. Wait 10 seconds.
    3. Press and hold the WPS button.
    4. Power on the router and continue holding WPS for 15–20 seconds, until the Power LED begins blinking rapidly.

  19. Return the PC’s IPv4 configuration to its previous automatic settings.

  20. Sign in at http://192.168.1.1. The router should now identify as an RT-AC68U with 64 MB of JFFS. The default username and password are admin / admin.

  21. Enable SSH as described in Step 10, then run the MTD5 repair commands below. The direct settings page is available at the router’s new address.

  22. After the repair is complete, the router can accept compatible ASUS, Asuswrt-Merlin, AdvancedTomato, FreshTomato, Tomato, or DD-WRT firmware.

Repair the MTD5 partition

Enter these commands in PuTTY after enabling SSH on the converted router:

cat /dev/mtd5 > /jffs/mtd5_backup.bin
mkdir /tmp/asus_jffs
mount -t jffs2 /dev/mtdblock5 /tmp/asus_jffs
rm -rf /tmp/asus_jffs/*
sync && umount /tmp/asus_jffs
rm -rf /jffs/.sys/RT-AC68U
nvram unset fw_check && nvram commit && reboot

References

Compatible firmware resources

Helpful information

  • ASUS Rebadger is a script that automates this process on a Windows 10 PC.
  • Merlin and official builds provide hardware acceleration, which may improve throughput on faster internet connections.
  • Check the router CPU speed on the System Information page.
  • If a 30/30/30 reset does not work, power off the router, hold Reset for 20 seconds, then power it on while continuing to hold Reset until the Power light blinks slowly.
  • If Mini-CFE and the ASUS Restore Utility both fail, consult the linked discussions before repeating a flash.
  • Additional discussion is available on the Whirlpool forums.

Restoring the RT-AC68U configuration after a rollback

  • The previously linked Google Docs restoration instructions are no longer available.
  • Mega.nz mirror