diff --git a/crates/chainspec/src/spec.rs b/crates/chainspec/src/spec.rs
index 2fd631fcd8..da12fd3ef1 100644
--- a/crates/chainspec/src/spec.rs
+++ b/crates/chainspec/src/spec.rs
@@ -33,7 +33,7 @@ use reth_network_peers::{
 
 /// The Ethereum mainnet spec
 pub static MAINNET: Lazy<Arc<ChainSpec>> = Lazy::new(|| {
-    ChainSpec {
+    let mut spec = ChainSpec {
         chain: Chain::mainnet(),
         genesis: serde_json::from_str(include_str!("../res/genesis/mainnet.json"))
             .expect("Can't deserialize Mainnet genesis json"),
@@ -52,13 +52,14 @@ pub static MAINNET: Lazy<Arc<ChainSpec>> = Lazy::new(|| {
         )),
         base_fee_params: BaseFeeParamsKind::Constant(BaseFeeParams::ethereum()),
         prune_delete_limit: 20000,
-    }
-    .into()
+    };
+    spec.genesis.config.dao_fork_support = true;
+    spec.into()
 });
 
 /// The Sepolia spec
 pub static SEPOLIA: Lazy<Arc<ChainSpec>> = Lazy::new(|| {
-    ChainSpec {
+    let mut spec = ChainSpec {
         chain: Chain::sepolia(),
         genesis: serde_json::from_str(include_str!("../res/genesis/sepolia.json"))
             .expect("Can't deserialize Sepolia genesis json"),
@@ -74,13 +75,14 @@ pub static SEPOLIA: Lazy<Arc<ChainSpec>> = Lazy::new(|| {
         )),
         base_fee_params: BaseFeeParamsKind::Constant(BaseFeeParams::ethereum()),
         prune_delete_limit: 10000,
-    }
-    .into()
+    };
+    spec.genesis.config.dao_fork_support = true;
+    spec.into()
 });
 
 /// The Holesky spec
 pub static HOLESKY: Lazy<Arc<ChainSpec>> = Lazy::new(|| {
-    ChainSpec {
+    let mut spec = ChainSpec {
         chain: Chain::holesky(),
         genesis: serde_json::from_str(include_str!("../res/genesis/holesky.json"))
             .expect("Can't deserialize Holesky genesis json"),
@@ -94,8 +96,9 @@ pub static HOLESKY: Lazy<Arc<ChainSpec>> = Lazy::new(|| {
         )),
         base_fee_params: BaseFeeParamsKind::Constant(BaseFeeParams::ethereum()),
         prune_delete_limit: 10000,
-    }
-    .into()
+    };
+    spec.genesis.config.dao_fork_support = true;
+    spec.into()
 });
 
 /// Dev testnet specification