The most important light sequences are:
PWR led:
Flashing (plugged) = it is charging
Solid (plugged) = fully charged
Slow flashing (not plugged) = low battery
GPS led:
Flashing = searching for a signal
Solid = GPS connection OK
CELL led:
Fast flashing = searching for network
Slow flashing = Cell connection OK
GPS blue solid + CELL green slow flashing = GEGO GPS connected OK