I will wait few days and will try to upgrade the firmware, but I don’t want to upgrade the firmware because of this other problem, with this other modem, which I am not sure is related to firmware version or not:
I am not sure is Verizon approved firmware - the latest firmware which I found at https://source.sierrawireless.com/, going to work for any provider on the planet?
Also, I am not sure will firmware upgrade actually is going to work.