@
samson
,
Thanks you for the link, i ll have a look,
I tested fews debug options and i was wrong about being dummy BGM but need to test with others games/options combined etc... (i think it was you to said there are one debug option who can enable that function, as i thinked also) but now watching the BBC news (with Navi X

)
Thanks you for Walking Dead (so it s working?)
(i agree also about eboot/elf part making it or block the bgm function, but here it s much more harder to understand than param.sfo, at least for me)
And last thing is i will not recommend to "force" that function and use it (and even if the game have it originally)