: I have asked in several related threads for anyone thats knows to tell us why/how
: the BS5 is necessary for MOTS operation but no one has posted a reply as yet.
It is not. The BS5 head unit is an (optional) wired remote to the BM5. To be more specific the BS5 has: 1) an LCD screen connected to the BM5 via DVI - mini HDMI (i.e. a secondary display); 2) a power source built in and sourced from the BM5 (4-pin socket) and 3) a "mouse wheel" (i.e. an USB powered controller). The BS5-related media player software is stored and executed on the BM5 - as there are no computing "electronics" in the BS5 - and it appears to be a separate program to the software created to operate the BM5 by itself (perhaps the reason why the BM5 has no browse function when the BS5 is hooked up to it as the two media player programs are independent from a "device" control point of view). Thus, the MOTS functionality seems to be disabled purposely when the USB plug connected to the BS5 is disconnected.