hack to write TS2 frames to a file 

diff --git a/src/debug.c b/src/debug.c
index 27fdb9c..5831e86 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -28,7 +28,7 @@
 
 #include <openbsc/debug.h>
 
-static unsigned int debug_mask = 0xffffffff & ~DMI;
+static unsigned int debug_mask = 0xffffffff & ~(DMI|DMIB);
 
 struct debug_info {
 	const char *name;