diff --git a/ports/arm/Makefile b/ports/arm/Makefile
index bde8ece..8689772 100644
--- a/ports/arm/Makefile
+++ b/ports/arm/Makefile
@@ -14,6 +14,4 @@ SRCS := $(SRCS) \
 		$(ATOMTHREADS_PORT)/atomport.c
 
 ASMS := $(ASMS) \
-		$(ATOMTHREADS_PORT)/atomport-asm.S
-
-
+		$(ATOMTHREADS_PORT)/atomport-asm.s
diff --git a/ports/arm/atomport-asm.S b/ports/arm/atomport-asm.s
similarity index 100%
rename from ports/arm/atomport-asm.S
rename to ports/arm/atomport-asm.s