Recovered from modem failure: OSError: AT+SMSWBOOT=3,0



  • My pyCom gPy device had an unresponsive lte modem.

    During a failed firmware upgrade, it spit out this exception:
    OSError: AT+SMSWBOOT=3,0 failed!

    Sending basic AT commands appeared to fail as well..

    > import LTE
    > lte=lTE()
    > lte.send_at_command('ATI')
    ''
    

    I recovered the modem by running the script supplied here by @jmarcelino

    #!/usr/bin/env python
    import struct
    import crc
    import stp
    import time
    import os
    from machine import UART
    from machine import SD
    
    
    FFF_FMT = "<4sIIIIIIIHHIHHIHHHH"
    FFF_SLIM_FMT = "<4sIIIIIIIHHHH"
    FFF_FEATURES_SLIM = 1 << 0
    FFF_MAGIC = "FFF!"
    
    SFFF_MAGIC = "SFFF"             # Firmware
    SUFF_MAGIC = "SUFF"             # Updater
    TEST_MAGIC = "TEST"             # Test
    DIFF_MAGIC = "DIFF"             # Diff Upgrade
    UPGR_MAGIC = "UPGR"             # Generic raw upgrade
    RASR_MAGIC = "RASR"             # Generic raw rasterize
    
    
    def read_rsp(s, size=None, timeout=-1):
        if timeout < 0:
            timeout = 20000
        elif timeout is None:
            timeout = 0
        while not s.any() and timeout > 0:
            time.sleep_ms(1)
            timeout -= 1
    
        if size is not None:
            rsp = s.read(size)
        else:
            rsp = s.read()
        if rsp is not None:
            return rsp
        else:
            return b''
    
    def print_pretty_response(rsp):
        lines = rsp.decode('ascii').split('\r\n')
        for line in lines:
            if line:
                print(line)
    
    
    def wait_for_modem(s, send=True, expected=b'OK'):
        while True:
            if send:
                s.write("AT\r\n")
            rsp = read_rsp(s, timeout=50)
            if expected in rsp:
                print()
                break
            else:
                print('.', end='', flush=True)
                time.sleep(0.5)
    
    def run(file_path, baudrate):
        abort = False
    
        print('<<< Welcome to the SQN3330 firmware updater >>>')
    
        if '/sd' in file_path:
            sd = SD()
            time.sleep(0.5)
            os.mount(sd, '/sd')
            time.sleep(0.5)
    
        blobsize = os.stat(file_path)[6]
        blob = open(file_path, "rb")
    
        if 'FiPy' in os.uname().sysname:
            pins = ('P20', 'P18', 'P19', 'P17')
        else:
            pins = ('P5', 'P98', 'P7', 'P99')
    
        s = UART(1, baudrate=baudrate, pins=pins, timeout_chars=100)
        s.read()
    
        # disable echo
        s.write("ATE0\r\n")
        response = read_rsp(s)
    
    #     print('Entering recovery mode')
    #     s.write("AT+SMSWBOOT=3,0\r\n")
    #     response = read_rsp(s)
    #     if b'OK' in response:
    #         print('Resetting.', end='', flush=True)
    #         s.write('AT^RESET\r\n')
    #         wait_for_modem(s, send=False, expected=b'+SHUTDOWN')
    #         time.sleep(2)
    #         wait_for_modem(s)
    #         s.write("AT\r\n")
    #         s.write("AT\r\n")
    #     else:
    #         raise OSError('AT+SMSWBOOT=3,0 failed!')
    # 
    #     time.sleep(1)
    #     s.read()
    
        print('Starting STP (DO NOT DISCONNECT POWER!!!)')
        s.write('AT+SMSTPU=\"ON_THE_FLY\"\r\n')
        response = read_rsp(s, size=4)
        if response != b'OK\r\n' and response != b'\r\nOK' and response != b'\nOK':
            raise OSError("Invalid answer '%s' from the device" % response)
            blob.close()
        s.read()
        try:
            stp.start(blob, blobsize, s, baudrate, AT=False)
            print('Code download done, returning to user mode')
        except:
            blob.close()
            print('Code download failed, aborting!')
            abort = True
    
        time.sleep(1.5)
        s.read()
        s.write("AT+SMSWBOOT=1,0\r\n")
        response = read_rsp(s)
    
        print('Resetting (DO NOT DISCONNECT POWER!!!).', end='', flush=True)
        time.sleep(1.5)
        s.write("AT^RESET\r\n")
        wait_for_modem(s, send=False, expected=b'+SHUTDOWN')
        time.sleep(2)
        wait_for_modem(s, send=False, expected=b'+SYSSTART')
    
        if not abort:
            time.sleep(0.5)
            print('Deploying the upgrade (DO NOT DISCONNECT POWER!!!)...')
            s.write("AT+SMUPGRADE\r\n")
            response = read_rsp(s, timeout=120000)
    
            print('Resetting (DO NOT DISCONNECT POWER!!!).', end='', flush=True)
            time.sleep(1.5)
            s.write("AT^RESET\r\n")
            wait_for_modem(s, send=False, expected=b'+SHUTDOWN')
            time.sleep(2)
            wait_for_modem(s, send=False, expected=b'+SYSSTART')
            s.write("AT\r\n")
            s.write("AT\r\n")
            time.sleep(0.5)
            s.read()
            print('Upgrade completed!')
            print("Here's the current firmware version:")
            time.sleep(0.5)
            s.read()
            s.write("ATI1\r\n")
            response = read_rsp(s)
            print_pretty_response(response)
    

    allowing it to run to COMPLETION (even though it appeared to hang for several minutes)

    at the end of completion, the script was able to query the modem for firmware version (it was old)

    I replaced the sqnsupgrade script with the original, and was able to run it to completion!

    >>> import sqnsupgrade
    >>> sqnsupgrade.run('/sd/FIPY_GPY_CATM1_33988.dup', 921600)
    <<< Welcome to the SQN3330 firmware updater >>>
    Entering recovery mode
    Resetting..
    
    Starting STP (DO NOT DISCONNECT POWER!!!)
    STP started
    Session opened: version 1, max transfer 8192 bytes
    Sending 5665583 bytes: [########################################] 100%
    Code download done, returning to user mode
    Resetting (DO NOT DISCONNECT POWER!!!)..
    ........
    Deploying the upgrade (DO NOT DISCONNECT POWER!!!)...
    Resetting (DO NOT DISCONNECT POWER!!!)..
    ...
    Upgrade completed!
    Here's the current firmware version:
    UE5.0.0.0c
    LR5.1.1.0-33988
    OK
    >>> 
    

 

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