diff --git a/cmd/evm/internal/t8ntool/transition.go b/cmd/evm/internal/t8ntool/transition.go
index cb7466d86..f63635687 100644
--- a/cmd/evm/internal/t8ntool/transition.go
+++ b/cmd/evm/internal/t8ntool/transition.go
@@ -250,9 +250,9 @@ func Transition(ctx *cli.Context) error {
 	if chainConfig.IsLondon(big.NewInt(int64(prestate.Env.Number))) {
 		if prestate.Env.BaseFee != nil {
 			// Already set, base fee has precedent over parent base fee.
-		} else if prestate.Env.ParentBaseFee != nil {
+		} else if prestate.Env.ParentBaseFee != nil && prestate.Env.Number != 0 {
 			parent := &types.Header{
-				Number:   new(big.Int).SetUint64(prestate.Env.Number),
+				Number:   new(big.Int).SetUint64(prestate.Env.Number - 1),
 				BaseFee:  prestate.Env.ParentBaseFee,
 				GasUsed:  prestate.Env.ParentGasUsed,
 				GasLimit: prestate.Env.ParentGasLimit,