Ended up googeling and found this forum post on the Raspberrypi forum. that explained how to correctly setup the file for WEP with open system:
network={Found an blogpost explaining how to edit the file:
ssid="myssid"
key_mgmt=NONE
wep_key0=mywepkey
wep_tx_keyidx=0
}
$ sudo nano /etc/wpa_supplicant/wpa_supplicant.confchanged myssid to the my wifi network ssid and changed the mywebkey to the correct key.
did a reboot
$ sudo rebootand now it works!
