How to revert back to stock firmware on ASUS RT-AC51U

Hello everyone,

in a bit of a pickle, so I could use and appreciate some assistance.

I installed without issue OpenWRT on the Asus RT-AC51U using the TFTP-client method as described on the Asus RT-AC51U table of hardware page. Unfortunately, I only realized that the 5Ghz is unsupported after installation once I came across the Unsupported: WiFi 5GHz page. This was me being stupid - lesson learnt.

In all other situations I would stick with OpenWRT even if it only had 2.4GHz wifi, but in this one case (local 2.4GHz network over-saturation) I need the 5GHz, so the only option is to return back to stock Asus firmware. Maybe OpenWRT will someday support the particular wlan card, but sadly I cannot wait.

I checked out the Back to original firmware page for general info and since there are no specific instructions on how to get back to stock on the router page, I am unsure how to proceed.

Do I just follow the mtd route with

mtd -r write /tmp/original_firmware.bin firmware
type or paste code here

Q: Is writing the stock firmware into the /tmp folder enough? Shutdown -r now after or anything else?

Q: The original firmware at Asus is in a .zip (, so what's the proper way of getting it into the router? Download on another device, unzip and copy via ssh? I know, this is a noobie question, but I am still at that level.

Any help would be appreciated, as I don't want to brick the thing, so asking now to save any potential issue.


side note: internal openwrt dot org links should not count towards the 2 links for new forum user limit.

Did you try flashing the stock firmware on the web GUI?

Nope. Is it really that simple? No risk of bricking?

There's a risk of bricking with any flash procedure.

Regardless, it's my understanding that if there was an issue, it would produce an error and fail, instead.

You can also download to /tmp and run sysupgrade -f foo.bin

Can't believe it was so simple. Was slightly worried about the default firmware being a .trx file (never seen that before), but uploaded and flashed via weg GUI without any issues.
Another reason why OpenWRT rocks!

Thanks for the help.

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