diff --git a/qemu-arm/memory.h b/qemu-arm/memory.h
deleted file mode 100644
index f3777b0e39..0000000000
--- a/qemu-arm/memory.h
+++ /dev/null
@@ -1,2 +0,0 @@
-// this is needed for extmod/crypto-algorithms/sha256.c
-#include <string.h>
diff --git a/stmhal/memory.h b/stmhal/memory.h
deleted file mode 100644
index f3777b0e39..0000000000
--- a/stmhal/memory.h
+++ /dev/null
@@ -1,2 +0,0 @@
-// this is needed for extmod/crypto-algorithms/sha256.c
-#include <string.h>