OK I fixed it! I went bleeding edge & downloaded retropie-buster-4.7.12-rpi4_400.img.gz and for whatever reason I was able to connect using the raspi-config script - I just entered my county code, SSID & password. So from my vantage point something got tweaked (eeprom update?) in the network setup routines in V4.7.1 - because it was working several months ago....

Thank you everybody for your help!

Yeah, probably, it's not that common with enterprise networks I guess. Thank you for making that clear though.

I actually solved it just now though.

For anyone wondering I managed to connect to the network on another machine (Ubuntu) and used Network Manager. I then checked the log (according to this link) with the command:

journalctl -u NetworkManager

This gave me this config for wpa_supplicant.conf:

country=SE ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 ap_scan=1 network={ ssid="Wifi-Name" scan_ssid=1 bgscan="simple:30:-65:300" key_mgmt=WPA-EAP WPA-EAP-SHA256 password="password" eap=PEAP fragment_size=1266 phase2="auth=MSCHAPV2" identity="username" proactive_key_caching=1 }

This might not work for everyone else since the configs are always different for every network. So be sure to do the same steps as I did if you can't get it to work.

So glad I finally got this, haha.

Hi,
thanks, I got it working now. After checking all different settings of my router hardware and the powerline adapters, I resetted the powerline / WiFi adapter to factory defaults an reconfigured it. Strange enough, without changing anything, it works now. I guess that it was a problem with the firmware of the powerline / WiFi adapter since the web interface wasn't available on this specific adapter as well.

Stupid question but I don't see it asked here:

Did you enable/configure SSH in the Software Configuration Menu on the new install in the Pi?

@misterkilgore Bluetooth has nothing to do with WIFI. That's how you ssh with WIFI. Maybe a problem with your router or network ?