diff --git a/packages/block/src/header.ts b/packages/block/src/header.ts
index f5eaaa840d..b7fc9ab5ed 100644
--- a/packages/block/src/header.ts
+++ b/packages/block/src/header.ts
@@ -184,7 +184,7 @@ export class BlockHeader {
         timestamp,
       })
     }
-    if (typeof setHardfork !== 'boolean') {
+    else if (typeof setHardfork !== 'boolean') {
       this._common.setHardforkBy({
         blockNumber: number,
         td: setHardfork as BigIntLike,
diff --git a/packages/vm/src/runBlock.ts b/packages/vm/src/runBlock.ts
index f6e05661a3..aa3d776e23 100644
--- a/packages/vm/src/runBlock.ts
+++ b/packages/vm/src/runBlock.ts
@@ -65,7 +65,7 @@ export async function runBlock(this: VM, opts: RunBlockOpts): Promise<RunBlockRe
         timestamp: block.header.timestamp,
       })
     }
-    if (typeof setHardforkUsed !== 'boolean') {
+    else if (typeof setHardforkUsed !== 'boolean') {
       this._common.setHardforkBy({
         blockNumber: block.header.number,
         td: setHardforkUsed,