diff --git a/boot/bootutil/src/image_ed25519.c b/boot/bootutil/src/image_ed25519.c
index 0d5e66df0..4e2423a08 100644
--- a/boot/bootutil/src/image_ed25519.c
+++ b/boot/bootutil/src/image_ed25519.c
@@ -12,6 +12,8 @@
 #ifdef MCUBOOT_SIGN_ED25519
 #include "bootutil/sign_key.h"
 
+/* We are not really using the MBEDTLS but need the ASN.1 parsing functions */
+#define MBEDTLS_ASN1_PARSE_C
 #include "mbedtls/oid.h"
 #include "mbedtls/asn1.h"