LTE Cat M1/NB-IoT Shield no longer registering to operators

Wireless & IoT Cellular
1

I have the LTE shield on a RedBoard Qwiic. At first, there was no problem. The device registered to Rogers on the first try and I could send hologram messages, send and receive SMS. After a couple of days, the device would lose connectivity on and off. Then, it would not connect to the operator at all. I have been trying to connect to any of the available three, including Rogers, for the past two days. I have tried taking it all over the city to rule out poor reception. The device no longer registers to any operator. RSSI is >30, I have 302610, 302720 and 302220 which are Bell, Rogers and Telus.

I have tried putting it on an Artemis ATP which Sparkfun advised was untested, so I put it on an uno to get it working. When my redboard qwiic came in, i swapped it out and it was working still. After these issues I have tried it again with the ATP, a regular uno, a mega, an osepp mega and the redboard but the issue persists.

Around the same time this started happening, the vanilla sparkfun library began returning memory full errors when trying to allocate memory for commands and responses.

I have a fully charged lipo on the shield, power supplied to the shield with the switch at the shield position and power supplied to the arduino with the switch at the arduino position makes no difference.

I know as time goes on with expired firmware the modem will develop invalid blocks of memory, but I can’t see it developing this quickly.

Any advice? It is weird that I watched the unit slowly become unable to do the one critical thing it is meant to do, which is connect to the outside world.

2

I swapped out the hologram sim to a particle electron and the electron connects no problem, so I’m ruling out signal strength and service availability.

I held the reset button on the LTE shield, tried again with the sparkfun library and still no connection. I’m leaning toward a firmware update being needed. The electron needed the new firmware before the SARA modem would connect with the hologram sim. I wanted LTE for longevity, since naturally 3G is the next to get shut down eventually but it will have to do for now.

I will look into writing a program to update the LTE shield, but as an end user firmware updates are not readily accessible to me. Again, any guidance from SparkFun would be greatly appreciated.

3

Correction, the electron doesn’t actually do anything. It breathes cyan but can’t connect anywhere. It performs a handshake with the hologram sim, but stops there. LTE shield still won’t connect.