1. If you mean SdrMiniport.sys is not working, we recommend you use user mode Umxsdrbrick.exe or Umxsdra.exe for your iperf test, they are equivalent in functions and better supported by Sora team.
2. If the iperf test is failed, please first test the UDP broadcast communication between 2 Sora MIMO kits. You can try get dump files at the receiver part to diagnose, normally you should set RX gain or channel or frequency offset to make one direction
work. Then you can reverse the UDP broadcast direction. If both works, the iperf (TCP) communication should be much easier to diagnose.