diff --git a/tests/misra/.gitignore b/tests/misra/.gitignore
index 8432f605..fc9ac228 100644
--- a/tests/misra/.gitignore
+++ b/tests/misra/.gitignore
@@ -1,4 +1,5 @@
 *.pdf
 *.txt
+.output.log
 new_table
 cppcheck/
diff --git a/tests/misra/test_misra.sh b/tests/misra/test_misra.sh
index 5504e3cd..cfc53bac 100755
--- a/tests/misra/test_misra.sh
+++ b/tests/misra/test_misra.sh
@@ -29,16 +29,19 @@ if [ -z "${SKIP_BUILD}" ]; then
 fi
 
 cppcheck() {
-  hashed_args=$(echo -n "$@$DIR" | md5sum | awk '{print $1}')
-  build_dir=/tmp/cppcheck_build/$hashed_args
-  mkdir -p $build_dir
-
+  # note that cppcheck build cache results in inconsistent results as of v2.13.0
+  OUTPUT=$DIR/.output.log
   $CPPCHECK_DIR/cppcheck --enable=all --force --inline-suppr -I $PANDA_DIR/board/ \
           -I $gcc_inc "$(arm-none-eabi-gcc -print-file-name=include)" \
           --suppressions-list=$DIR/suppressions.txt --suppress=*:*inc/* \
           --suppress=*:*include/* --error-exitcode=2 --addon=misra \
-          --check-level=exhaustive --cppcheck-build-dir=$build_dir \
-          "$@"
+          --check-level=exhaustive "$@" |& tee $OUTPUT
+
+  # cppcheck bug: some MISRA errors won't result in the error exit code,
+  # so check the output (https://trac.cppcheck.net/ticket/12440#no1)
+  if grep "misra violation" $OUTPUT > /dev/null; then
+    exit 1
+  fi
 }
 
 printf "\n${GREEN}** PANDA F4 CODE **${NC}\n"
diff --git a/tests/misra/test_mutation.py b/tests/misra/test_mutation.py
index f50d27c7..cc3666f1 100755
--- a/tests/misra/test_mutation.py
+++ b/tests/misra/test_mutation.py
@@ -5,7 +5,6 @@ import pytest
 import shutil
 import subprocess
 import tempfile
-import hashlib
 import random
 
 HERE = os.path.abspath(os.path.dirname(__file__))
@@ -68,25 +67,18 @@ for p in patterns:
 
 @pytest.mark.parametrize("fn, patch, should_fail", mutations)
 def test_misra_mutation(fn, patch, should_fail):
-  key = hashlib.md5((str(fn) + str(patch)).encode()).hexdigest()
-  tmp = os.path.join(tempfile.gettempdir(), key)
+  with tempfile.TemporaryDirectory() as tmp:
+    shutil.copytree(ROOT, tmp, dirs_exist_ok=True)
 
-  if os.path.exists(tmp):
-    shutil.rmtree(tmp)
-  shutil.copytree(ROOT, tmp)
+    # apply patch
+    if fn is not None:
+      r = os.system(f"cd {tmp} && sed -i '{patch}' {fn}")
+      assert r == 0
 
-  # apply patch
-  if fn is not None:
-    r = os.system(f"cd {tmp} && sed -i '{patch}' {fn}")
-    assert r == 0
-
-  # run test
-  env = {'SKIP_BUILD': '1'} | os.environ.copy()
-  r = subprocess.run("tests/misra/test_misra.sh", cwd=tmp, shell=True, env=env)
-  failed = r.returncode != 0
-  assert failed == should_fail
-
-  shutil.rmtree(tmp)
+    # run test
+    r = subprocess.run("tests/misra/test_misra.sh", cwd=tmp, shell=True)
+    failed = r.returncode != 0
+    assert failed == should_fail
 
 if __name__ == "__main__":
   pytest.main([__file__, "-n 8"])