It is tested that ECUHELP KT200 is able to read/write ECU BMW MSV90 and read password yes, need open ecu.

(Image 1: thanks to Pancho Samperio)

Use KT200 to read/write Msv90 ECU in Boot mode.
Here is the wiring diagram to refer:

To sum up:
KT200 can read the password for MSV90 via OBD first, then read/write ecu in boot mode, please click on the “info” in KT200 software to refer to the step-by-step procedure.