I am using a couple of USB-KW41Z dongles, on wich the K22F and KW41-K firmwares were previously erased with a J-Link probe. Now I am trying to get them back to their original state, so that I can program them with a simple drag-and-drop procedure.
I have reflashed the K22F and KW41Z with the original sniffer files (\tools\wireless\binaries\sniffer_usbkw41z_k22f.bin and \tools\wireless\binaries\sniffer_usbkw41z_kw41z.bin respectively). The dongles work correctly as a sniffers with the Kinetis Protocol Analyzer and WireShark.
However I can't get them to enumate as a Mass Storage Device (I plug them while keeping the "KW41Z reset" button pressed and release it after a few seconds). They only show up as a Virtual COM Port in Windows 10's Device Manager.
What can be done to fix this?