diff --git a/consensus/beacon/consensus.go b/consensus/beacon/consensus.go
index c716ba4dcc..1db9d81a1d 100644
--- a/consensus/beacon/consensus.go
+++ b/consensus/beacon/consensus.go
@@ -462,6 +462,10 @@ func (beacon *Beacon) InnerEngine() consensus.Engine {
 	return beacon.ethone
 }
 
+func (beacon *Beacon) SwapInner(inner consensus.Engine) {
+	beacon.ethone = inner
+}
+
 // SetThreads updates the mining threads. Delegate the call
 // to the eth1 engine if it's threaded.
 func (beacon *Beacon) SetThreads(threads int) {
@@ -478,13 +482,9 @@ func (beacon *Beacon) SetThreads(threads int) {
 // If the parentHash is not stored in the database a UnknownAncestor error is returned.
 func IsTTDReached(chain consensus.ChainHeaderReader, parentHash common.Hash, parentNumber uint64) (bool, error) {
 	if cfg := chain.Config(); cfg.Optimism != nil {
-		num := parentNumber
-		if num == ^(uint64(0)) { // caller can (intentionally?!) underflow on parent-of-block 0 case.
-			num = 0
-		}
-		if cfg.IsBedrock(new(big.Int).SetUint64(num)) {
-			return true, nil
-		}
+		// If OP-Stack then bedrock activation number determines when TTD (eth Merge) has been reached.
+		// Note: some tests/utils will set parentNumber == max_uint64 as "parent" of the genesis block, this is fine.
+		return cfg.IsBedrock(new(big.Int).SetUint64(parentNumber + 1)), nil
 	}
 	if chain.Config().TerminalTotalDifficulty == nil {
 		return false, nil
diff --git a/consensus/beacon/oplegacy.go b/consensus/beacon/oplegacy.go
index 3c30cd24dc..90d7e8678e 100644
--- a/consensus/beacon/oplegacy.go
+++ b/consensus/beacon/oplegacy.go
@@ -29,8 +29,8 @@ func (o *OpLegacy) VerifyHeader(chain consensus.ChainHeaderReader, header *types
 func (o *OpLegacy) VerifyHeaders(chain consensus.ChainHeaderReader, headers []*types.Header) (chan<- struct{}, <-chan error) {
 	quit := make(chan struct{}, 1)
 	result := make(chan error, len(headers))
-	for range headers {
-		result <- nil
+	for _, h := range headers {
+		result <- o.VerifyHeader(chain, h)
 	}
 	return quit, result
 }
diff --git a/core/chain_makers.go b/core/chain_makers.go
index 90b5b1fcee..22c837e84f 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -319,7 +319,7 @@ func GenerateChain(config *params.ChainConfig, parent *types.Block, engine conse
 		// to a chain, so the difficulty will be left unset (nil). Set it here to the
 		// correct value.
 		if b.header.Difficulty == nil {
-			if config.TerminalTotalDifficulty == nil {
+			if config.TerminalTotalDifficulty == nil && !config.IsOptimismBedrock(b.header.Number) {
 				// Clique chain
 				b.header.Difficulty = big.NewInt(2)
 			} else {
diff --git a/core/types/receipt.go b/core/types/receipt.go
index b85df05a3a..02410c3132 100644
--- a/core/types/receipt.go
+++ b/core/types/receipt.go
@@ -569,7 +569,7 @@ func (rs Receipts) DeriveFields(config *params.ChainConfig, hash common.Hash, nu
 			logIndex++
 		}
 	}
-	if config.Optimism != nil && len(txs) >= 2 { // need at least an info tx and a non-info tx
+	if config.Optimism != nil && len(txs) >= 2 && config.IsBedrock(new(big.Int).SetUint64(number)) { // need at least an info tx and a non-info tx
 		l1Basefee, costFunc, feeScalar, err := extractL1GasParams(config, time, txs[0].Data())
 		if err != nil {
 			return err
diff --git a/core/types/receipt_test.go b/core/types/receipt_test.go
index f6a3598ca9..5c3789b8e1 100644
--- a/core/types/receipt_test.go
+++ b/core/types/receipt_test.go
@@ -34,8 +34,16 @@ import (
 )
 
 var (
+	bedrockGenesisTestConfig = func() *params.ChainConfig {
+		conf := *params.AllCliqueProtocolChanges // copy the config
+		conf.Clique = nil
+		conf.TerminalTotalDifficultyPassed = true
+		conf.BedrockBlock = big.NewInt(0)
+		conf.Optimism = &params.OptimismConfig{EIP1559Elasticity: 50, EIP1559Denominator: 10}
+		return &conf
+	}()
 	ecotoneTestConfig = func() *params.ChainConfig {
-		conf := *params.OptimismTestConfig // copy the config
+		conf := *bedrockGenesisTestConfig // copy the config
 		time := uint64(0)
 		conf.EcotoneTime = &time
 		return &conf
@@ -774,7 +782,7 @@ func TestDeriveOptimismBedrockTxReceipts(t *testing.T) {
 	// Re-derive receipts.
 	basefee := big.NewInt(1000)
 	derivedReceipts := clearComputedFieldsOnReceipts(receipts)
-	err := Receipts(derivedReceipts).DeriveFields(params.OptimismTestConfig, blockHash, blockNumber.Uint64(), 0, basefee, nil, txs)
+	err := Receipts(derivedReceipts).DeriveFields(bedrockGenesisTestConfig, blockHash, blockNumber.Uint64(), 0, basefee, nil, txs)
 	if err != nil {
 		t.Fatalf("DeriveFields(...) = %v, want <nil>", err)
 	}
@@ -802,7 +810,7 @@ func TestDeriveOptimismEcotoneTxReceipts(t *testing.T) {
 	basefee := big.NewInt(1000)
 	derivedReceipts := clearComputedFieldsOnReceipts(receipts)
 	// Should error out if we try to process this with a pre-Ecotone config
-	err := Receipts(derivedReceipts).DeriveFields(params.OptimismTestConfig, blockHash, blockNumber.Uint64(), 0, basefee, nil, txs)
+	err := Receipts(derivedReceipts).DeriveFields(bedrockGenesisTestConfig, blockHash, blockNumber.Uint64(), 0, basefee, nil, txs)
 	if err == nil {
 		t.Fatalf("expected error from deriving ecotone receipts with pre-ecotone config, got none")
 	}
diff --git a/ethclient/ethclient_test.go b/ethclient/ethclient_test.go
index c2b8748110..2b6f19f447 100644
--- a/ethclient/ethclient_test.go
+++ b/ethclient/ethclient_test.go
@@ -29,6 +29,8 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/consensus/beacon"
 	"github.com/ethereum/go-ethereum/internal/ethapi"
 
 	"github.com/ethereum/go-ethereum"
@@ -286,8 +288,21 @@ func newMockHistoricalBackend(t *testing.T) string {
 func newTestBackend(t *testing.T, enableHistoricalState bool) (*node.Node, []*types.Block) {
 	histAddr := newMockHistoricalBackend(t)
 
-	// Generate test chain.
-	blocks := generateTestChain(enableHistoricalState)
+	var consensusEngine consensus.Engine
+	var actualGenesis *core.Genesis
+	var chainLength int
+	if enableHistoricalState {
+		actualGenesis = genesisForHistorical
+		consensusEngine = beacon.New(ethash.NewFaker())
+		chainLength = 10
+	} else {
+		actualGenesis = genesis
+		consensusEngine = ethash.NewFaker()
+		chainLength = 2
+	}
+
+	// Generate test chain
+	blocks := generateTestChain(consensusEngine, actualGenesis, chainLength)
 
 	// Create node
 	n, err := node.New(&node.Config{})
@@ -295,12 +310,6 @@ func newTestBackend(t *testing.T, enableHistoricalState bool) (*node.Node, []*ty
 		t.Fatalf("can't create new node: %v", err)
 	}
 	// Create Ethereum Service
-	var actualGenesis *core.Genesis
-	if enableHistoricalState {
-		actualGenesis = genesisForHistorical
-	} else {
-		actualGenesis = genesis
-	}
 	config := &ethconfig.Config{Genesis: actualGenesis}
 	if enableHistoricalState {
 		config.RollupHistoricalRPC = histAddr
@@ -310,6 +319,9 @@ func newTestBackend(t *testing.T, enableHistoricalState bool) (*node.Node, []*ty
 	if err != nil {
 		t.Fatalf("can't create new ethereum service: %v", err)
 	}
+	if enableHistoricalState { // swap to the pre-bedrock consensus-engine that we used to generate the historical blocks
+		ethservice.BlockChain().Engine().(*beacon.Beacon).SwapInner(ethash.NewFaker())
+	}
 	// Import the test chain.
 	if err := n.Start(); err != nil {
 		t.Fatalf("can't start test node: %v", err)
@@ -317,30 +329,29 @@ func newTestBackend(t *testing.T, enableHistoricalState bool) (*node.Node, []*ty
 	if _, err := ethservice.BlockChain().InsertChain(blocks[1:]); err != nil {
 		t.Fatalf("can't import test blocks: %v", err)
 	}
+	if enableHistoricalState {
+		// Now that we have a filled DB, swap the pre-Bedrock consensus to OpLegacy,
+		// which does not support re-processing of pre-bedrock data.
+		ethservice.Engine().(*beacon.Beacon).SwapInner(&beacon.OpLegacy{})
+	}
 	return n, blocks
 }
 
-func generateTestChain(enableHistoricalState bool) []*types.Block {
+func generateTestChain(consensusEngine consensus.Engine, genesis *core.Genesis, length int) []*types.Block {
 	generate := func(i int, g *core.BlockGen) {
 		g.OffsetTime(5)
 		g.SetExtra([]byte("test"))
 		if i == 1 {
 			// Test transactions are included in block #2.
-			if enableHistoricalState {
+			if genesis.Config.Optimism != nil && genesis.Config.IsBedrock(big.NewInt(1)) {
 				g.AddTx(depositTx)
 			}
 			g.AddTx(testTx1)
 			g.AddTx(testTx2)
 		}
 	}
-	var actualGenesis *core.Genesis
-	if enableHistoricalState {
-		actualGenesis = genesisForHistorical
-	} else {
-		actualGenesis = genesis
-	}
-	_, blocks, _ := core.GenerateChainWithGenesis(actualGenesis, ethash.NewFaker(), 2, generate)
-	return append([]*types.Block{actualGenesis.ToBlock()}, blocks...)
+	_, blocks, _ := core.GenerateChainWithGenesis(genesis, consensusEngine, length, generate)
+	return append([]*types.Block{genesis.ToBlock()}, blocks...)
 }
 
 func TestEthClientHistoricalBackend(t *testing.T) {