diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
index d5e090044..3e7984aa7 100644
--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@@ -3017,12 +3017,7 @@ func (bc *Blockchain) verifyTxWitnesses(t *transaction.Transaction, block *block
 
 // verifyHeaderWitnesses is a block-specific implementation of VerifyWitnesses logic.
 func (bc *Blockchain) verifyHeaderWitnesses(currHeader, prevHeader *block.Header) error {
-	var hash util.Uint160
-	if prevHeader == nil && currHeader.PrevHash.Equals(util.Uint256{}) {
-		hash = currHeader.Script.ScriptHash()
-	} else {
-		hash = prevHeader.NextConsensus
-	}
+	hash := prevHeader.NextConsensus
 	_, err := bc.VerifyWitness(hash, currHeader, &currHeader.Script, HeaderVerificationGasLimit)
 	return err
 }
diff --git a/pkg/services/oracle/request.go b/pkg/services/oracle/request.go
index 6267f55d0..1607fa56a 100644
--- a/pkg/services/oracle/request.go
+++ b/pkg/services/oracle/request.go
@@ -157,6 +157,11 @@ func (o *Oracle) processRequest(priv *keys.PrivateKey, req request) error {
 				resp.Code = transaction.Error
 			}
 		case neofs.URIScheme:
+			if len(o.MainCfg.NeoFS.Nodes) == 0 {
+				o.Log.Warn("no NeoFS nodes configured", zap.String("url", req.Req.URL))
+				resp.Code = transaction.Error
+				break
+			}
 			ctx, cancel := context.WithTimeout(context.Background(), o.MainCfg.NeoFS.Timeout)
 			defer cancel()
 			index := (int(req.ID) + incTx.attempts) % len(o.MainCfg.NeoFS.Nodes)