--- xnu/xnu-344.21.73/iokit/Kernel/IOStartIOKit.cpp
+++ xnu/xnu-344.49/iokit/Kernel/IOStartIOKit.cpp
@@ -112,8 +112,6 @@
     clock_initialize_calendar();
 }
 
-// From <osfmk/kern/debug.c>
-extern int debug_mode;
 
 void StartIOKit( void * p1, void * p2, void * p3, void * p4 )
 {
@@ -131,11 +129,6 @@
 
     if( PE_parse_boot_arg( "io", &debugFlags ))
 	gIOKitDebug = debugFlags;
-
-    // Check for the log synchronous bit set in io
-    if (gIOKitDebug & kIOLogSynchronous)
-        debug_mode = true;
-
     //
     // Have to start IOKit environment before we attempt to start
     // the C++ runtime environment.  At some stage we have to clean up
@@ -147,6 +140,7 @@
     OSlibkernInit();
 
     IOLog("_cppInit done\n");
+
 
    /*****
     * Declare the fake kmod_info structs for built-in components