diff --git a/package/avm/misdn-user/misdn-user.conf b/package/avm/misdn-user/misdn-user.conf
index c99a40f3c..3d13ad1ea 100644
--- a/package/avm/misdn-user/misdn-user.conf
+++ b/package/avm/misdn-user/misdn-user.conf
@@ -1,4 +1,9 @@
+
 misdnuser_custmain() {
+	# the kernel might be build without the mISDN patch applied
+	tar xvjf $archdir/mISDN_for_PBX4Linux-3.0.tar.bz2 mISDN/include/linux
+	var_append CC_WRAPPER_INSERT " " "-I $PWD/mISDN/include"
+
 	eval make $makeopt
 	mkdir -p $includedir/mISDN
 	mkdir -p $libdir/mISDN/i4lnet
@@ -8,6 +13,9 @@ misdnuser_custmain() {
 	install -v include/*.h $includedir/mISDN/
 	install -v i4lnet/*.h $includedir/mISDN/i4lnet/
 	install -v voip/*.h $includedir/mISDN/voip/
+
+	mkdir -p $includedir/mISDN/linux
+	cp mISDN/include/linux/*.h $includedir/mISDN/linux/
 }
 
 custmain="misdnuser_custmain"