After renew to Volumio 3.0, my connection to my 5Ghz wifi is lost and can’t even see it in setting.
After tons of trying and researches, final I’ve got it working. This is the easiest way without getting into SSF:
1: Mount your sd card into a pc.
2: Open the /boot directory [There are actually 3 partitions!]
3: Create a text file and name it “wpa_supplicat.conf”
4: Paste the following into file:
(make sure you have the 2 letters “iso country code” for your country, in my case country=CA which is Canada, check:https://countrycode.org/ )
(also make sure you have type the correct “5Ghz wifi ssid” and password!)
5: “Save” this file in your boot directory
6: Unmount the sd card first before taking it out (Very Important !!!)
7: insert into your Pi before you start it.
Now you should connected to your 5Ghz network after Volumio open.