diff --git a/drivers/measured_boot/rss/rss_measured_boot.c b/drivers/measured_boot/rss/rss_measured_boot.c
index 1b2f177..258aa8d 100644
--- a/drivers/measured_boot/rss/rss_measured_boot.c
+++ b/drivers/measured_boot/rss/rss_measured_boot.c
@@ -32,6 +32,19 @@
 #  error Invalid Measured Boot algorithm.
 #endif /* MBOOT_ALG_ID */
 
+#if ENABLE_ASSERTIONS
+static bool null_arr(const uint8_t *signer_id, size_t signer_id_size)
+{
+	for (size_t i = 0U; i < signer_id_size; i++) {
+		if (signer_id[i] != 0U) {
+			return false;
+		}
+	}
+
+	return true;
+}
+#endif /* ENABLE_ASSERTIONS */
+
 /* Functions' declarations */
 void rss_measured_boot_init(struct rss_mboot_metadata *metadata_ptr)
 {
@@ -39,6 +52,7 @@
 
 	/* Init the non-const members of the metadata structure */
 	while (metadata_ptr->id != RSS_MBOOT_INVALID_ID) {
+		assert(null_arr(metadata_ptr->signer_id, MBOOT_DIGEST_SIZE));
 		metadata_ptr->sw_type_size =
 			strlen((const char *)&metadata_ptr->sw_type) + 1;
 		metadata_ptr++;
@@ -93,36 +107,53 @@
 }
 
 int rss_mboot_set_signer_id(struct rss_mboot_metadata *metadata_ptr,
-			    unsigned int img_id,
+			    const void *pk_oid,
 			    const void *pk_ptr,
 			    size_t pk_len)
 {
 	unsigned char hash_data[CRYPTO_MD_MAX_SIZE];
 	int rc;
+	bool hash_calc_done = false;
 
 	assert(metadata_ptr != NULL);
 
-	/* Get the metadata associated with this image. */
-	while ((metadata_ptr->id != RSS_MBOOT_INVALID_ID) &&
-		(metadata_ptr->id != img_id)) {
-		metadata_ptr++;
-	}
+	/*
+	 * Do an exhaustive search over the platform metadata to find
+	 * all images whose key OID matches the one passed in argument.
+	 *
+	 * Note that it is not an error if do not get any matches.
+	 * The platform may decide not to measure all of the images
+	 * in the system.
+	 */
+	while (metadata_ptr->id != RSS_MBOOT_INVALID_ID) {
+		/* Get the metadata associated with this key-oid */
+		if (metadata_ptr->pk_oid == pk_oid) {
+			if (!hash_calc_done) {
+				/* Calculate public key hash */
+				rc = crypto_mod_calc_hash(CRYPTO_MD_ID,
+							  (void *)pk_ptr,
+							  pk_len, hash_data);
+				if (rc != 0) {
+					return rc;
+				}
 
-	/* If image is not present in metadata array then skip */
-	if (metadata_ptr->id == RSS_MBOOT_INVALID_ID) {
-		return 0;
-	}
+				hash_calc_done = true;
+			}
 
-	/* Calculate public key hash */
-	rc = crypto_mod_calc_hash(CRYPTO_MD_ID, (void *)pk_ptr,
-				  pk_len, hash_data);
-	if (rc != 0) {
-		return rc;
-	}
+			/*
+			 * Fill the signer-ID field with the newly/already
+			 * computed hash of the public key and update its
+			 * signer ID size field with compile-time decided
+			 * digest size.
+			 */
+			(void)memcpy(metadata_ptr->signer_id,
+				     hash_data,
+				     MBOOT_DIGEST_SIZE);
+			metadata_ptr->signer_id_size = MBOOT_DIGEST_SIZE;
+		}
 
-	/* Update metadata struct with the received signer_id */
-	(void)memcpy(metadata_ptr->signer_id, hash_data, MBOOT_DIGEST_SIZE);
-	metadata_ptr->signer_id_size = MBOOT_DIGEST_SIZE;
+		metadata_ptr++;
+	}
 
 	return 0;
 }
diff --git a/include/drivers/measured_boot/rss/rss_measured_boot.h b/include/drivers/measured_boot/rss/rss_measured_boot.h
index 76affd8..7ab517c 100644
--- a/include/drivers/measured_boot/rss/rss_measured_boot.h
+++ b/include/drivers/measured_boot/rss/rss_measured_boot.h
@@ -40,6 +40,7 @@
 	size_t  version_size;
 	uint8_t sw_type[SW_TYPE_MAX_SIZE];
 	size_t  sw_type_size;
+	void    *pk_oid;
 	bool    lock_measurement;
 };
 
@@ -49,9 +50,8 @@
 				 uintptr_t data_base, uint32_t data_size,
 				 uint32_t data_id);
 
-/* TODO: These metadata are currently not available during TF-A boot */
 int rss_mboot_set_signer_id(struct rss_mboot_metadata *metadata_ptr,
-			    unsigned int img_id, const void *pk_ptr,
+			    const void *pk_oid, const void *pk_ptr,
 			    size_t pk_len);
 
 #endif /* RSS_MEASURED_BOOT_H */