diff --git a/configs/constant_presets/mainnet.yaml b/configs/constant_presets/mainnet.yaml
index 629badcee..6ce6ec7f7 100644
--- a/configs/constant_presets/mainnet.yaml
+++ b/configs/constant_presets/mainnet.yaml
@@ -44,7 +44,7 @@ EFFECTIVE_BALANCE_INCREMENT: 1000000000
 GENESIS_FORK_VERSION: 0x00000000
 # 0, GENESIS_EPOCH is derived from this constant
 GENESIS_SLOT: 0
-BLS_WITHDRAWAL_PREFIX: 0
+BLS_WITHDRAWAL_PREFIX: 0x00
 
 
 # Time parameters
diff --git a/configs/constant_presets/minimal.yaml b/configs/constant_presets/minimal.yaml
index 1d0ad015d..fd9684a0c 100644
--- a/configs/constant_presets/minimal.yaml
+++ b/configs/constant_presets/minimal.yaml
@@ -43,7 +43,7 @@ EFFECTIVE_BALANCE_INCREMENT: 1000000000
 GENESIS_FORK_VERSION: 0x00000000
 # 0, GENESIS_EPOCH is derived from this constant
 GENESIS_SLOT: 0
-BLS_WITHDRAWAL_PREFIX: 0
+BLS_WITHDRAWAL_PREFIX: 0x00
 
 
 # Time parameters