Firmware is invalid on old Asus Rt-n56u

Installing and Using OpenWrt
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I’m not sure if this is the right forum to post in. Here’s my issue: I recently updated the original firmware of my old Asus RT-n56u A1 router to the latest version. I’ve been trying to flash WRT firmware to it, but the intended bin file is invalid. When I try to flash the chip, it says “invalid file.” When I updated the firmware with the Asus firmware, the file was a “Trx” file. I changed the WRT firmware file type from “bin” to “trx,” which worked until I tried to flash it to the RT-56U. According to what I read, the RT rejected the file. I’m supposed to use the recovery tool from Asus, but it’s not a flash component. There’s an upgrade portion in the system, but I’m not sure how to use it. I’m trying to flash the WRT firmware, but I’m not getting any luck. What am I doing wrong? I’m ready to quit this process. Please help. So sorry about the length of this post. `

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  • Can you provide a screenshot or better description of the issue
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First check the TOH page for the device. https://openwrt.org/toh/asus/rt-n56u

Under Installation https://openwrt.org/toh/asus/rt-n56u#installation see the the Notice - It is recommended to use the
https://openwrt.org/toh/asusrtn56u#installation_via_asus_firmware_restoration_tool

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![Screenshot 2026-05-15 230825|560x499](upload://waomFS57gYL79yTupDNSd6oDOEI.png)
here is screenshot .
I am trying the wiki instructions now and the instructions say to do the following:
1. Download and install the ASUS Firmware Restoration tool from the [ASUS Support page](https://www.asus.com/us/supportonly/rt-n56u/helpdesk_download/)

2. Download the sysupgrade image from OpenWrt  done

3. Enter Recovery Mode

  1. Unplug Router  done

  2. Hold Reset Button and Plug in Router  done

  3. Release button when front LED flashes slowly
4. Use the following to set up your TCP/IP settings:

  1. IP address: 192.168.1.10  done, but doesn't work, I assume that they want me to go to 192.168.1.1 to get to the Asus interface of the router  but done

  2. Subnet mask: 255.255.255.0  done
5. **Disconnect or disable ALL other network interfaces BEFORE opening the “Firmware Restoration” Tool!** Other network interfaces may interfere with the tool.

6. Open the Firmware Restoration tool. It doesn't do anything but installs. That is when I go to the Asus router interface w/ 1.1. Had to reconnect the cable to get it to interface, but done

7. Select the sysupgrade.bin and upload.  done. This is where the screenshot is taken from. No uploads are happening because of invalid file.

8. After it uploads the file, it will tell you to power the router off and back on

9. Wait for the power light to stop flashing

10. Telnet, SSH or use your browser to access the router on 192.168.1.1

11. If you had to disconnect or disable other network interfaces, you can now reconnect or enable them
5

Please read reply to lleachii. [1]

Screenshot 2026-05-15 230825
Screenshot 2026-05-15 230825979×873 107 KB

here is screenshot .
I am trying the wiki instructions now, and the instructions say to do the following:

  1. Download and install the ASUS Firmware Restoration tool from the ASUS Support page

  2. Download the sysupgrade image from OpenWrt "done"

  3. Enter Recovery Mode

  4. Unplug Router "done"

  5. Hold Reset Button and Plug in Router "done"

  6. Release button when front LED flashes slowly

  7. Use the following to set up your TCP/IP settings:

  8. IP address: 192.168.1.10 "done, but doesn't work, I assume that they want me to go to 192.168.1.1 to get to the Asus interface of the router" "done"

  9. Subnet mask: 255.255.255.0 "done"

  10. Disconnect or disable ALL other network interfaces BEFORE opening the “Firmware Restoration” Tool! Other network interfaces may interfere with the tool.

  11. Open the Firmware Restoration tool. "Doesn't do anything but installs. That is when I go to the Asus router interface w/ 1.1. Had to reconnect the cable to get it to interface, but "done."

  12. Select the sysupgrade.bin and upload ''done'' ''this is where the screenshot is taken from. No uploads are happening because of invalid file.''

  13. After it uploads the file, it will tell you to power the router off and back on

  14. Wait for the power light to stop flashing

  15. Telnet, SSH or use your browser to access the router on 192.168.1.1

  16. If you had to disconnect or disable other network interfaces, you can now reconnect or enable them

  1. Footnotes ↩︎

6

Telnet should be removed from the wiki, hasn't been used for ages.

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Thanks for your help, frolic. Yeah, I will definitely try that.

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No, your assumption is incorrect.

See the warning under https://openwrt.org/toh/asus/rt-n56u#installation_via_webui for a an explanation.

Have you tried the TFTP Installation method?

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No, this is a separate windows app. Flashing this model does not involve the OEM web interface at all.

Wireless Router] How to use Rescue Mode (Firmware Restoration)

(https://www.asus.com/us/support/faq/1000814/)

PC- 192.168.1.10
Asus router - in Rescue Mode - 192.168.1.1 on Lan1/port1

Follow wiki.

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Thank you, cookiemonster, for the video and your reply. I followed your instructions, and it finally worked, using the restoration firmware app. Thank you, thank you, thank you!!!!

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Thank you, RuralRoots, for the assistance. I DID indeed try to use the TFTP method; however, I was unable to get the TFTP working, despite seeing the services loaded and the client added. Not sure what was wrong, but I was successfully able to load OpenWRT using the Firmware Restoration tool. Success at last!!! Again, thank you for your reply and your assistance.