The problem is that I am no longer able to see the LTE modem in Ubuntu after upgrading the firmware.
Earlier I reported performance metrics on the Quectel EM06-A LTE Modem. Since then, I upgraded the BIOS/UEFI firmware and the embedded controller firmware. It could be unrelated, but I am unable to see the LTE Modem in the Ubuntu 20.04.4 LTS Settings/Network page.
I can talk to the modem using socat. I used diff with and without the modem card installed to see that it is using /dev/ttyUSB0, /dev/ttyUSB1, /dev/ttyUSB2 and /dev/ttyUSB3. Is there an easier way to find these devices, i.e., is this documented somewhere? I could not find it in the Quectel AT Command reference guide.
The ATI command shows
ATI
Quectel
EM06
Revision: EM06ALAR03A05M4G
OK
The AT+CIMI shows there is a sim card and that card has an IMEI
AT+CIMI
310************
OK
The AT+GMR command shows the modem firmware version. I looked here for firmware information but can’t find anything about firmware.
AT+GMR
EM06ALAR03A05M4G
OK
I also cleaned the connector on the modem card and tried an alternate sim, but the results are the same.
Suggestions are appreciated.