Hi all !
After firmware to version 23.05.5 wifi 5 ghz unknown device on archer c20 v4 and v5
rolled back to version 23.05.4
I understand that version 23.05.5 is still raw?
I downloaded the firmware from here https://firmware-selector.openwrt.org/?version=23.05.5&target=ramips%2Fmt76x8&id=tplink_archer-c20-v5
I re-uploaded the firmware, but wifi 5 GHz is not active and as I understand it, there is no driver for it, so it does not work
only works 2.4 GHz
Most likely caused by https://github.com/openwrt/firmware-selector-openwrt-org/issues/42, your device has kmod-mt76x2 as a device package which is a wireless driver, with that gone wireless will not work as expected.
2 Likes
Well, yes, it is.
i reset the settings to default, logged in via Luci and WiFi 5 GHz is not even on the list
looks like another glitch in firmware-selector.openwrt.org
Yesterday I updated to the new version and everything seemed to be working, and then I went into Luci and saw that some clients were missing, I looked closely, and there was no 5 GHz wifi, I left them without internet for about 40 minutes and no one called me, didn't ask why 
If you must create an image from the Firmware Selector, just be sure to add the needed kmod package for your 5 GHz WiFi. This was discussed in the official 23.05.5 thread you posted in - you seemed to overlook it (there's a lot of posts).
Otherwise, feel free to try: https://downloads.openwrt.org/releases/23.05.5/targets/ramips/mt76x8/openwrt-23.05.5-ramips-mt76x8-tplink_archer-c20-v5-squashfs-sysupgrade.bin
We understand that the official build does not have the missing kmod issue.
To be clear, if you make any previous versions (including 23.05.4) or SNAPSHOT from the Firmware Selector site at this time, the issue will also occur.