One radio "not" working - xiaomi mir3g, fresh openwrt install

[bhyde]

Sorry to be a pest, but I'm stuck.

I have recently installed openwrt[1] on a xiaomi 3rg, aka mir3g. The 5G wireless isn't working and I need advise about how to diagnose what's wrong.

• Thanks for any help! - ben

Details:

When enabled the GUI shows the radio as 0%.
I can scan for access points, i can even attach to one of them.
Things that don't change the situation:

1. restarting the radio
2. changing the channel, ssid, encryption.
3. changing the number of wifi-iface.
4. restoring a config from backup.
5. rebooting, of course

This is my config, radio1 is the problem.

config wifi-device 'radio0'
	option type 'mac80211'
	option channel '11'
	option hwmode '11g'
	option path 'pci0000:00/0000:00:00.0/0000:01:00.0'
	option htmode 'HT20'
	option country '00'
	option legacy_rates '1'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option encryption 'psk2'
	option key 'secretsanta'
	option ssid 'wireless@cozy.org'

config wifi-device 'radio1'
	option type 'mac80211'
	option hwmode '11a'
	option path 'pci0000:00/0000:00:01.0/0000:02:00.0'
	option htmode 'VHT80'
	option country '00'
	option legacy_rates '1'
	option channel '112'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option encryption 'psk2'
	option key 'secretsanta'
	option ssid 'wireless-5g-new@cozy.org'

[1] OpenWrt 18.06.1 r7258-5eb055306f / LuCI openwrt-18.06 branch (git-18.228.31946-f64b152)