diff --git a/.travis.yml b/.travis.yml
index cc1e614a23..bb0ad50ba4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -46,10 +46,7 @@ script:
     - ./dist/tools/licenses/check.sh master --diff-filter=MR --error-exitcode=0 || exit
     - ./dist/tools/licenses/check.sh master --diff-filter=AC || exit
 
-# TODO:
-#   Remove the `AC` argument when all headers have been
-#   taken care of in master.
-    - ./dist/tools/externc/check.sh master AC || exit
+    - ./dist/tools/externc/check.sh master || exit
 
 # TODO:
 #   Remove all but `master` parameters to cppcheck (and remove second
diff --git a/dist/tools/externc/check.sh b/dist/tools/externc/check.sh
index c83ec323f8..7311be26b5 100755
--- a/dist/tools/externc/check.sh
+++ b/dist/tools/externc/check.sh
@@ -21,9 +21,11 @@ else
     FILES="$(git diff --diff-filter=${DIFFFILTER} --name-only ${BRANCH} | grep -E '\.h$')"
 fi
 
+FILES=$(echo "${FILES}" | grep -v -E '^(dist/tools|boards/msba2-common/tools/)')
+
 # check files
 for FILE in ${FILES}; do
-    if head -100 "${ROOT}/${FILE}" \
+    if cat "${ROOT}/${FILE}" \
         | sed -e 's/$/ /' \
         | tr -d '\r\n' \
         | sed -e 's/  */ /g' \