diff --git a/igvm_defs/src/lib.rs b/igvm_defs/src/lib.rs
index 7d11fd2..45f836f 100644
--- a/igvm_defs/src/lib.rs
+++ b/igvm_defs/src/lib.rs
@@ -469,7 +469,7 @@ pub struct SnpPolicy {
     pub abi_major: u8,
     #[bits(1)]
     pub smt: u8,
-    #[bits(1)]
+    #[bits(1, default = 1)]
     pub reserved_must_be_one: u8,
     #[bits(1)]
     pub migrate_ma: u8,