A few years we have been using successfully a  DEBUGADPTR1-USB (USB debug Adapter from SILABS) with our own designed Boards, Simplicity Studio v4, under Windows 7

 Target was , usually C8051F380.

Now, after installing latest Simplicity Studio v4 to my new PC with Windows10 and new INTEL i9-9400 CPU, installation of SS v4 looks OK, but,

with same USB debug Adapter, I CAN NOT start DEBUG session with message :

"Adapter IF Invalid Parameter e.g. the serial number may be wrong "

Please help !

Thanks, Erik !

I have older Version of C8051F120DK dev. Kit with Serial Adapter EC2...
question is :
can I use this EC2 serial Adapter to work/debug newer Silabs MCUs such as
C8051F996-C-GU and/or
C8051F920-GQ
mounted on my own target Board
... using just two signals/wires (C2D and C2CK)
from JTAG/DEBUG cable/connector ?