diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index 21bf3e7a6..bb3d5269c 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -1517,8 +1517,8 @@ def get_genesis_beacon_state(genesis_validator_deposits: List[Deposit],
         slot=GENESIS_SLOT,
         genesis_time=genesis_time,
         fork=Fork(
-            previous_version=GENESIS_FORK_VERSION,
-            current_version=GENESIS_FORK_VERSION,
+            previous_version=int_to_bytes4(GENESIS_FORK_VERSION),
+            current_version=int_to_bytes4(GENESIS_FORK_VERSION),
             epoch=GENESIS_EPOCH,
         ),