diff --git a/pkg/micro-ecc/Makefile.include b/pkg/micro-ecc/Makefile.include
index 1bb685e1b8..a40d330c1d 100644
--- a/pkg/micro-ecc/Makefile.include
+++ b/pkg/micro-ecc/Makefile.include
@@ -1 +1,7 @@
 INCLUDES += -I$(PKGDIRBASE)/micro-ecc
+
+ifneq (,$(filter cortex-m0%,$(CPU_ARCH)))
+  # LLVM/clang can't handle the inline assembler instructions on M0 in this
+  # package
+  TOOLCHAINS_BLACKLIST += llvm
+endif