diff --git a/core/genesis.go b/core/genesis.go
index 68d945e37e..394409ad3e 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -459,8 +459,12 @@ func (g *Genesis) toBlockWithRoot(root common.Hash) *types.Block {
 	if g.GasLimit == 0 {
 		head.GasLimit = params.GenesisGasLimit
 	}
-	if g.Difficulty == nil && g.Mixhash == (common.Hash{}) {
-		head.Difficulty = params.GenesisDifficulty
+	if g.Difficulty == nil {
+		if g.Config != nil && g.Config.Ethash == nil {
+			head.Difficulty = big.NewInt(0)
+		} else if g.Mixhash == (common.Hash{}) {
+			head.Difficulty = params.GenesisDifficulty
+		}
 	}
 	if g.Config != nil && g.Config.IsLondon(common.Big0) {
 		if g.BaseFee != nil {