Connecting to WIFI: Guru Meditation Error

  • Hi,

    i am currently trying to connect to a WPA2-Enterprise (eduroam) network as described here on a Lopy4 with Pysense Expansion board.
    This is my file (no other files are used in this project):

    from network import WLAN
    from machine import SD
    import os
    import time
    sd = SD()
    os.mount(sd, '/sd')
    wlan = WLAN(mode=WLAN.STA)
    nets = wlan.scan()
    for net in nets:
        if net.ssid == "eduroam" and ==
            print('Wifi found. connecting.')
            wlan.connect(ssid='eduroam', auth=(WLAN.WPA2_ENT, '[username]', '[pw]'),
                         identity='[identy]', ca_certs='/sd/cert/ca.pem')

    The device boots up and runs the script without error. However wlan.isconnected() will always return False.

    Then, after a couple of seconds the device crashes with the error message:

    >>> Guru Meditation Error: Core  0 panic'ed (LoadProhibited)
    . Exception was unhandled.
    Register dump:
    PC      : 0x40188721  PS      : 0x00060630  A0      : 0x801832fa  A1      : 0x3ffe39f0
    A2      : 0x3ffe3f9c  A3      : 0x00000001  A4      : 0x3fbc64a4  A5      : 0x00000001
    A6      : 0x3ffe3ac4  A7      : 0x00000001  A8      : 0x8018871d  A9      : 0x3ffe4988
    A10     : 0x00000000  A11     : 0x000000ff  A12     : 0x3ffe3f9c  A13     : 0x00000000
    A14     : 0x00000002  A15     : 0x00000005  SAR     : 0x00000018  EXCCAUSE: 0x0000001c
    EXCVADDR: 0x00000001  LBEG    : 0x40187509  LEND    : 0x4018750f  LCOUNT  : 0x00000000

    After a long sequence of printed core dumping the system will restart.

    The device is apparently setting up the connection in the background and will at some point fail. I investigated the Guru Meditation error (details here) and found that:

    LoadProhibited, StoreProhibited:

    This CPU exception happens when application attempts to read from or write to an invalid memory location. The address which was written/read is found in EXCVADDR register in the register dump. If this address is zero, it usually means that application attempted to dereference a NULL pointer. If this address is close to zero, it usually means that application attempted to access member of a structure, but the pointer to the structure was NULL. If this address is something else (garbage value, not in 0x3fxxxxxx - 0x6xxxxxxx range), it likely means that the pointer used to access the data was either not initialized or was corrupted.

    So apparently the application attempted to access member of a structure, but the pointer to the structure was NULL. That doesn't really help me, however.

    Is anybody facing the same problem or has some advice?

    Notes on the code:

    I am checking as eduroam is available at least twice on different channels. The Lopy4 is set on channel 6 and I also find on instance of eduroam on this channel. I don't know if that is important as my problem persists and I can't connect to WIFI either way.

    The ca.pem file that I have stored on SD is the same that I am using on my Ubuntu Laptop to (successfully) connect to eduroam.

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