To connect libreelec to wifi via the command line
# connmanctl enable wifi
# connmanctl scan wifi
# connmanctl services
Will list known wifi services.
*AO Wired                ethernet_001e06365853_cable
*A  davids.net.IOT       wifi_000f55b13b7e_6461766964732e6e65742e494f54_managed_psk
davids.net           wifi_000f55b13b7e_6461766964732e6e6574_managed_psk
davids.net Guest     wifi_000f55b13b7e_6461766964732e6e6574204775657374_managed_none
Create an access file in /storage/.cache/connman
eg /storage/.cache/connman/davids.net.IOT.config
[global]
Name = IOT
Description = IOT Wifi service config file
[service_wifi_IOT]
Type = wifi
Name = davids.net.IOT
Passphrase = XXXXXX
or use
SSID = 
instead of
Name = 
giving the hex code instead of ASCII