diff --git a/pkg/cryptoauthlib/Makefile.dep b/pkg/cryptoauthlib/Makefile.dep
index d71411f502..cff48ab08a 100644
--- a/pkg/cryptoauthlib/Makefile.dep
+++ b/pkg/cryptoauthlib/Makefile.dep
@@ -9,3 +9,7 @@ ifneq (,$(filter cryptoauthlib_test,$(USEMODULE)))
   USEMODULE += cryptoauthlib_test_tng
   USEMODULE += cryptoauthlib_test_atcacert
 endif
+
+# Some EFM32 CPU families define AES_COUNT, which is also defined by this
+# library.
+FEATURES_BLACKLIST += arch_efm32