diff --git a/boot/bootutil/include/bootutil/crypto/ecdsa.h b/boot/bootutil/include/bootutil/crypto/ecdsa.h
index a6f4ebe7a..e577f988d 100644
--- a/boot/bootutil/include/bootutil/crypto/ecdsa.h
+++ b/boot/bootutil/include/bootutil/crypto/ecdsa.h
@@ -132,8 +132,6 @@ static int bootutil_import_key(uint8_t **cp, uint8_t *end)
 }
 #endif /* MCUBOOT_USE_TINYCRYPT || MCUBOOT_USE_MBED_TLS || MCUBOOT_USE_CC310 */
 
-#if defined(MCUBOOT_USE_TINYCRYPT)
-#ifndef MCUBOOT_ECDSA_NEED_ASN1_SIG
 /*
  * cp points to ASN1 string containing an integer.
  * Verify the tag, and that the length is 32 bytes. Helper function.
@@ -183,8 +181,8 @@ static int bootutil_decode_sig(uint8_t signature[NUM_ECC_BYTES * 2], uint8_t *cp
     }
     return 0;
 }
-#endif /* not MCUBOOT_ECDSA_NEED_ASN1_SIG */
 
+#if defined(MCUBOOT_USE_TINYCRYPT)
 typedef uintptr_t bootutil_ecdsa_context;
 static inline void bootutil_ecdsa_init(bootutil_ecdsa_context *ctx)
 {
@@ -253,8 +251,12 @@ static inline int bootutil_ecdsa_verify(bootutil_ecdsa_context *ctx,
 {
     (void)ctx;
     (void)pk_len;
-    (void)sig_len;
     (void)hash_len;
+    uint8_t dsig[2 * NUM_ECC_BYTES];
+
+    if (bootutil_decode_sig(dsig, sig, sig + sig_len)) {
+        return -1;
+    }
 
     /* Only support uncompressed keys. */
     if (pk[0] != 0x04) {
@@ -262,7 +264,7 @@ static inline int bootutil_ecdsa_verify(bootutil_ecdsa_context *ctx,
     }
     pk++;
 
-    return cc310_ecdsa_verify_secp256r1(hash, pk, sig, BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE);
+    return cc310_ecdsa_verify_secp256r1(hash, pk, dsig, BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE);
 }
 
 static inline int bootutil_ecdsa_parse_public_key(bootutil_ecdsa_context *ctx,
@@ -619,7 +621,11 @@ static inline int bootutil_ecdsa_p256_verify(bootutil_ecdsa_p256_context *ctx,
 {
     (void)ctx;
     (void)pk_len;
-    (void)sig_len;
+    uint8_t dsig[2 * NUM_ECC_BYTES];
+
+    if (bootutil_decode_sig(dsig, sig, sig + sig_len)) {
+        return -1;
+    }
 
 	/* As described on the compact representation in IETF protocols,
 	 * the first byte of the key defines if the ECC points are
@@ -632,7 +638,7 @@ static inline int bootutil_ecdsa_p256_verify(bootutil_ecdsa_p256_context *ctx,
 	pk++;
 
     return bl_secp256r1_validate(hash, BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE,
-                                 pk, sig);
+                                 pk, dsig);
 }
 #endif /* MCUBOOT_USE_NRF_EXTERNAL_CRYPTO */