diff --git a/simulators/ethereum/engine/config/cancun/constants.go b/simulators/ethereum/engine/config/cancun/constants.go
index 8e5a15c2da..801c14610e 100644
--- a/simulators/ethereum/engine/config/cancun/constants.go
+++ b/simulators/ethereum/engine/config/cancun/constants.go
@@ -22,8 +22,8 @@ var (
 	BLOB_COMMITMENT_VERSION_KZG = byte(0x01)
 
 	// EIP 4788
-	BEACON_ROOTS_ADDRESS  = common.HexToAddress("0xbEAC020008aFF7331c0A389CB2AAb67597567d7a")
-	HISTORY_BUFFER_LENGTH = uint64(98304)
+	BEACON_ROOTS_ADDRESS  = common.HexToAddress("0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02")
+	HISTORY_BUFFER_LENGTH = uint64(8191)
 
 	// Test constants
 	DATAHASH_START_ADDRESS = big.NewInt(0x20000)
diff --git a/simulators/ethereum/engine/config/cancun/genesis.go b/simulators/ethereum/engine/config/cancun/genesis.go
index d8a7765147..3043ccdc99 100644
--- a/simulators/ethereum/engine/config/cancun/genesis.go
+++ b/simulators/ethereum/engine/config/cancun/genesis.go
@@ -30,7 +30,7 @@ func ConfigGenesis(genesis *core.Genesis, forkTimestamp uint64) error {
 	genesis.Alloc[BEACON_ROOTS_ADDRESS] = core.GenesisAccount{
 		Balance: common.Big0,
 		Nonce:   1,
-		Code:    common.Hex2Bytes("3373fffffffffffffffffffffffffffffffffffffffe14604457602036146024575f5ffd5b620180005f350680545f35146037575f5ffd5b6201800001545f5260205ff35b6201800042064281555f359062018000015500"),
+		Code:    common.Hex2Bytes("0x3373fffffffffffffffffffffffffffffffffffffffe14604d57602036146024575f5ffd5b5f35801560495762001fff810690815414603c575f5ffd5b62001fff01545f5260205ff35b5f5ffd5b62001fff42064281555f359062001fff015500"),
 	}
 
 	return nil
diff --git a/simulators/ethereum/pyspec/Dockerfile b/simulators/ethereum/pyspec/Dockerfile
index 529857039d..1ce323dde1 100644
--- a/simulators/ethereum/pyspec/Dockerfile
+++ b/simulators/ethereum/pyspec/Dockerfile
@@ -21,8 +21,8 @@ COPY --from=builder /source/pyspec/pyspec .
 # To run locally generated fixtures, comment the following RUN lines and
 # uncomment the ADD line.
 # Download the latest fixture release.
-RUN wget https://github.com/ethereum/execution-spec-tests/releases/download/v1.0.4/fixtures_hive.tar.gz
-RUN tar -xzvf fixtures_hive.tar.gz
+RUN wget https://github.com/ethereum/execution-spec-tests/releases/latest/download/fixtures_develop_hive.tar.gz
+RUN tar -xzvf fixtures_develop_hive.tar.gz
 RUN mv fixtures /fixtures
 
 # ADD ./pyspec/fixtures /fixtures