diff --git a/src/include/kernel/ext_manifest.h b/src/include/kernel/ext_manifest.h
index 496342873..17fd262fd 100644
--- a/src/include/kernel/ext_manifest.h
+++ b/src/include/kernel/ext_manifest.h
@@ -95,7 +95,7 @@ struct ext_man_dbg_abi {
 struct ext_man_config_data {
 	struct ext_man_elem_header hdr;
 
-	struct config_elem elems[EXT_MAN_CONFIG_LAST_ELEM];
+	struct config_elem elems[];
 } __packed;
 
 #endif /* __KERNEL_EXT_MANIFEST_H__ */
diff --git a/src/init/ext_manifest.c b/src/init/ext_manifest.c
index 2e9b5b557..6568ffebf 100644
--- a/src/init/ext_manifest.c
+++ b/src/init/ext_manifest.c
@@ -85,10 +85,14 @@ const struct ext_man_dbg_abi ext_man_dbg_info
 	},
 };
 
+/* increment this value after adding any element to ext_man_config dictionary */
+#define CONFIG_ELEM_CNT (EXT_MAN_CONFIG_LAST_ELEM - 1)
+
 const struct ext_man_config_data ext_man_config
 	__aligned(EXT_MAN_ALIGN) __section(".fw_metadata") = {
 	.hdr.type = EXT_MAN_ELEM_CONFIG_DATA,
-	.hdr.elem_size = ALIGN_UP(sizeof(struct ext_man_config_data),
+	.hdr.elem_size = ALIGN_UP(sizeof(struct ext_man_config_data) +
+				  sizeof(struct config_elem) * CONFIG_ELEM_CNT,
 				  EXT_MAN_ALIGN),
 	.elems = {
 		{EXT_MAN_CONFIG_IPC_MSG_SIZE, SOF_IPC_MSG_MAX_SIZE},