FiPy, LTE: Regression error - no band 8 support

[robert-hh]

With the change of firmware 1.20.0.rc12.1 to 1.20.0.rc13 I get the following error, when attaching the modem:

>>> from network import LTE
>>> lte = LTE()
>>> lte.attach(band=8, apn="iot.1nce.net")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: band 8 not supported by this board hardware!

The error is caused by the calls to
lteppp_send_at_command(&cmd, &modlte_rsp);

The command is copied in, but the command length is not set, and then the AT command fails. So e.g. after line 622, the following line must be added:
cmd.dataLen = strlen("AT+SMDD");
At two other places, where lteppp_send_at_command() is called, similar changes have to be made. Then attach works with specifying a band.
Edit: It looks like the error was introduced between v1.20.0.rc11 and v1.20.0.rc12.

[svonbentzel]

@robert-hh Great work! Thank you 🙏

[robert-hh]

@robert-hh Fixed by replacing the calls to lteppp_send_at_command() with lte_push_at_cmd_ext() (and the appropriate parameters), which also sets the length data field. File here https://github.com/pycom/pycom-micropython-sigfox/files/3586300/modlte.zip