[Modem Start-up] Open modem firmware fails to load.

Currently Ofonoctl fails to bring-up the open modem firmware which is created by Biktorgj. I already investigated this issue and came up with a solution. Problem is I'm not able to fork this repository and create a pull request for this fix. The systemd service file would need to be rewritten as following:

[Unit]
Description=Poweron-Modem
After=ofono.service

[Service]
Type=oneshot
ExecStart=/usr/bin/ofonoctl online
RemainAfterExit=yes
Restart=on-failure
RestartSec=10

[Install]
WantedBy=default.target

In this service script I removed the 15 sec "sleep" timer. I changed type from simple to oneshot to enable the use of the Restart function. RemainAfterExit=yes is necessary to maintain the same behaviour of the service as it was with Type=simple The restart function chosen is: on-fail, because when the modem is not ready yet during boot te service ofonoctl will return "failure". RestartSec timer is 10 seconds, which makes the service retry every 10 seconds until the service is started successfully eventually.

This change has been tested with 29 April 2021 image, and with stock (Quectel) and open (Biktorgj) firmware. I have not encountered any issues using this altered service.