Missing 5GHz radio on Elecom WRC-1750GHBK2-I with OpenWRT 19.07.4

I flashed my Elecom WRC-1750GHBK2-I with OpenWRT 19.07.4 by using its factory web interface. Going to Network -> Wireless, A 2.4GHz radio (radio0) exists, but the 5 Ghz radio is not on the page. I had been using both radios with the factory firmware before flashing. Factory firmware is the latest version.

I configured radio0, try to connect one device to it and can see it in the OpenWRT gui.
Router's WAN port is not connected.

I tried to reboot (System -> Reboot) and it seems that OpenWRT is reset back to freshly installed state: (1) it forgets the new root password I set and says "no password set!" and radio0 (2.4GHz) becomes disabled. The 5GHz radio is still missing.

Router tech data:

OpenWRT firmware that I used:

root@OpenWrt:~# uci show wireless

System log

Kernel log

Pls read intallation instruction carefully:

1. Boot WRC-1750GHBK2-I/C normaly
2. Access to "" and open firmware upgrade page
("フゑームウェを更新 ζ‰‹ε‹•ζ›΄ζ–°οΌˆγ‚’γƒƒγƒ—γƒ‡γƒΌγƒˆοΌ‰")
3. Select the OpenWrt factory image and click apply ("適用") button
to perform firmware update
4. On the (initramfs) factory image, perform sysupgrade with
squashfs-sysupgrade image
5. Wait ~150 seconds to complete flashing

You skip point 4 of this instruction.

Thank you for you reply.
Yes! I did not do step 4. How exactly do I do that? ssh into the router and execute

squashfs-sysupgrade image


After flashing initramfs-factory.bin in its web interface flash squashfs-sysupgrade image

Just to make sure, I worry bricking the router. The OpenWRT web interface runs on the router. Could I flash your linked image using that? ie System -> Backup/Flash Firmware -> Flash new firmware image (Upload a sysupgrade-compatible image here to replace the running firmware.)?

Edit: OpenWRT web interface runs

initramfs-factory.bin is not intended for regular usage. Only for tests and sysupgrade. Initramfs images don't save settings.


Thank you very much for helping. I appreciate your patience in linking me details.
The 5g radio is found and settings are saving. The router is working for me. I end of up using the sysupgrade image (19.07.4) below as it matches the version of initramfs-factory (19.07.4) that I first installed. Serge's link earlier is to 19.07.3. I flash the sysupgrade image via OpenWRT's GUI.


Thank you to @musashino who also helped me on Twitter.
I hope more people will benefit from your contributions to this project.

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