you have a bricked midiphy LoopA?
you made a failure while uploading a new firmware? or you had a Blackout, or your computer died, or you removed the USB-Cable too soon? or you closed mios studio while uploading???
and everthing else didnt help (bootloadermode - jumper...).
this video is is the solution.
...
https://www.youtube.com/watch?v=HlapIP3P5Jo