Why not using Channel 1-8 with BLHeli? Spektreworks carrier board

just a quick question… Why shouldn’t i use the channels 1-8 when using esc with BLHeli as stated in the Wiki? http://ardupilot.org/copter/docs/common-dshot.html?highlight=blheli

This is more or less inconvenient as i’m using the spektreworks carrier board. As far as I tried i couldn’t get the ZTW Spider Escs to work with the pixhawk… Any suggestions? I set the mode to Dshot150 but the motors don’t spin…

Because the code doesn’t support output from the IO processor (chan 1-8) only the main FMU which are available on 9-16. Also, are you sure those ESC’s support Dshot? I have some of those (quite old now) and they do not.