> 1 - Can I listen the signal with command X? What configs should I change to
> make that happening?
Depends, experiment with the different bits in the X command.
But first of all collect as much protocol information as possible on the device
from the internet.
> 2 - If command X is the way to go, how can I interpret the captured result
Read the commandref.html carefully from the beginning to the end.
> and send it back with CUL commands?
There is a G for raw commands, but it only can send data with a special
> where could be a good starting point?
Compiling culfw first is a good start, then take a look at rf_receive.c
> Can I use Raspberry pi dfu-programmer to upload the changed firmware?
Yes, as descibed in commandref.html