lte.attach() doesn't work, but modem is attached

  • Hi,

    I am trying to work with a GPy (NB-IoT), configured to only listen to Band 28, which is the band I'm using with a mobile EPC (Ericsson) I own.
    After configuring the SIM card, the modem tries to connect/attach to the cellular network and I can spot it on the MME and eNodeB (including a set of initializing messages). The modem is then given an IP address dynamically, an S-GW and a P-GW and it's state changes from "Idle" to "Active".

    I can 'ping' the modem and can 'traceroute' it to see it communicating through the right APN (configured on both SIM and Core).
    When I try the AT command - 'AT+CEREG?' I get the following answer: 2, 2, "0002", "XXXXXXX",9
    As I understand it, it means: configured to register to network, registered to network, location tag (which is the right NB-IoT cell), cell ID in hexa, some cause that I couldn't figure out what it means but seems irrelevant.

    If I try to lte.attach(), the modem won't attach and it will stay with lte.isattached() = False.
    Ideas on how to proceed and an explanation of what is the lte.attach() trying to do would be welcome.



  • Indeed, that was the issue. With the new Firmware it's working.
    Thank you.

  • @shedaim I don't know which f/w you're using, but maybe this would be helpful:

    @robert-hh said in Trying to connect to LTE-M1:

    @chielvdiepen There is a problem in the lte.attach() API. @xykon adresses this in a trial firmware build at
    Please download and install that (install from file). It may fix you problem.
    See also this thread around and


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