Sorry I've updated my post in which I was complaining that I wasn't able to connect with USB.
=> I've done it accordingly to information provided through below links:
So disappointed! RC connection with Spark only fly 100meters and...
DJI Spark connect to controller though usb not wifi!
and it worked.
For anyone with the same issue, steps are "simply":
- Spark RC powered on
- Smartphone powered on (WiFi disable of course & DJI GO 4 not opened)
- Connect the male micro-USB/female USB cable & the male USB/male micro-USB cable (not required if you have an OTG male micro-USB / male micro-USB cable)
- Connect first the cable to the Spark RC by the male micro-USB connector from the male micro-USB/female USB cable (or connect your OTG male micro-USB / male micro-USB cable)
- Connect then the smartphone to the other male micro-USB connector
- Then your smartphone (Android) should ask you if you want to open DJI GO 4 App each time for this device => YES
- Finally DJI GO 4 App will open and you'll be able to click on "ENTER DEVICE >" to open the "Spark RC interface".
Just in case, a trick to reduce video lags if you connect in WiFi mode: Do not activate auto-updates through WiFi for the Play Store applications & do not activate also auto sytem updates for your OS.
Initially I had HUGE video lags in WiFi, and when I change above settings it completly change this (wasn't perfect but usable).