diff --git a/xyz/openbmc_project/State/Boot/PostCode.interface.yaml b/xyz/openbmc_project/State/Boot/PostCode.interface.yaml
index 2ea20b4..0dea5c7 100644
--- a/xyz/openbmc_project/State/Boot/PostCode.interface.yaml
+++ b/xyz/openbmc_project/State/Boot/PostCode.interface.yaml
@@ -28,7 +28,7 @@
               oldest boot cycle.
       returns:
         - name: Codes
-          type: dict[uint64, uint64]
+          type: dict[uint64, struct[uint64,array[byte]]]
           description: >
             An array of post codes and timestamp in microseconds since epoch
     - name: GetPostCodes
@@ -43,6 +43,6 @@
               oldest boot cycle.
       returns:
         - name: Codes
-          type: array[uint64]
+          type: array[struct[uint64,array[byte]]]
           description: >
             An array of post codes of one boot cycle.