There was only one small bluetooth patch in v47. And commands which are in old post show if your problem is related to this patch. No output means this problem has nothing with bluetooth l2cap patch. ==== How to find where is this problem: I thought that this problem is with l2cap patch (but from Darkslayer post, it is not true). I do not have bluetooth headset, so I cannot reproduce this bug. So the only way is using git bisect on my git repository and find which commit break bluetooth. But this must do someone who can test this problem, can use git and compile+flash kernel.