You can start reading what i’ve posted in the forum:
https://mangoh.discourse.group/t/bluetooth-le-on-mangoh-red-with-iot-card/1960
There is a couple more information that I’ve finally found like modifying bt-init.sh by removing the mux command and replacing them by the ones quoted in this post:
https://mangoh.discourse.group/t/error-when-starting-bluetooth-util/834
Good luck ! (it’s sometimes not easy to find to find information)
nkau