diff --git a/internal/native/client.go b/internal/native/client.go
index ee5f34a..f606957 100644
--- a/internal/native/client.go
+++ b/internal/native/client.go
@@ -231,7 +231,7 @@ func (c *Client) VerifyHash(containerID, objectID, expectedHash string) VerifyHa
 	if err != nil {
 		return VerifyHashResponse{Success: false, Error: err.Error()}
 	}
-	actualHash := hex.EncodeToString(hasher.Sum(make([]byte, 0, sha256.Size)))
+	actualHash := hex.EncodeToString(hasher.Sum(nil))
 	if actualHash != expectedHash {
 		return VerifyHashResponse{Success: true, Error: "hash mismatch"}
 	}
diff --git a/internal/registry/obj_registry.go b/internal/registry/obj_registry.go
index fb44bed..0caed21 100644
--- a/internal/registry/obj_registry.go
+++ b/internal/registry/obj_registry.go
@@ -3,6 +3,7 @@ package registry
 import (
 	"encoding/binary"
 	"encoding/json"
+	"errors"
 	"os"
 	"time"
 
@@ -15,7 +16,7 @@ type ObjRegistry struct {
 }
 
 const (
-	// Indicates that an object was created, but its data wasn't verified yet
+	// Indicates that an object was created, but its data wasn't verified yet.
 	statusCreated = "created"
 )
 
@@ -87,7 +88,7 @@ func (o *ObjRegistry) SetObjectStatus(id uint64, newStatus string) error {
 
 		objBytes := b.Get(encodeId(id))
 		if objBytes == nil {
-			return nil
+			return errors.New("object doesn't exist")
 		}
 
 		obj := new(ObjectInfo)
@@ -112,20 +113,19 @@ func (o *ObjRegistry) GetObjectCountInStatus(status string) (int, error) {
 			return nil
 		}
 
-		c := b.Cursor()
-		for keyBytes, objBytes := c.First(); keyBytes != nil; keyBytes, objBytes = c.Next() {
+		return b.ForEach(func(_, objBytes []byte) error {
 			if objBytes != nil {
 				var obj ObjectInfo
 				if err := json.Unmarshal(objBytes, &obj); err != nil {
 					// Ignore malformed objects
-					continue
+					return nil
 				}
 				if obj.Status == status {
 					objCount++
 				}
 			}
-		}
-		return nil
+			return nil
+		})
 	})
 	return objCount, err
 }
diff --git a/internal/registry/obj_selector.go b/internal/registry/obj_selector.go
index 613a75e..8efe5d6 100644
--- a/internal/registry/obj_selector.go
+++ b/internal/registry/obj_selector.go
@@ -2,6 +2,7 @@ package registry
 
 import (
 	"encoding/json"
+	"errors"
 	"sync"
 
 	"go.etcd.io/bbolt"
@@ -59,14 +60,10 @@ func (o *ObjSelector) NextObject() (*ObjectInfo, error) {
 		// Update the last key
 		if keyBytes != nil {
 			o.lastId = decodeId(keyBytes)
-		} else {
-			// Loopback to beginning so that we can revisit objects which were taken for verification
-			// but their status wasn't changed
-			// TODO: stop looping back to beginning too quickly
-			o.lastId = 0
+			return nil
 		}
 
-		return nil
+		return errors.New("no objects are available")
 	})
 	return foundObj, err
 }
diff --git a/internal/registry/registry.go b/internal/registry/registry.go
index 67359ee..f1cb8f9 100644
--- a/internal/registry/registry.go
+++ b/internal/registry/registry.go
@@ -49,7 +49,7 @@ func (r *Registry) Exports() modules.Exports {
 // Open creates a new instance of object registry that will store information about objects
 // in the specified file. If repository instance for the file was previously created, then
 // Open will return the existing instance of repository, because bolt database allows only
-// one write connection at a time
+// one write connection at a time.
 func (r *Registry) Open(dbFilePath string) *ObjRegistry {
 	r.root.mu.Lock()
 	defer r.root.mu.Unlock()
diff --git a/internal/s3/client.go b/internal/s3/client.go
index 3c1ec33..747a9ed 100644
--- a/internal/s3/client.go
+++ b/internal/s3/client.go
@@ -120,7 +120,7 @@ func (c *Client) VerifyHash(bucket, key, expectedHash string) VerifyHashResponse
 	if err != nil {
 		return VerifyHashResponse{Success: false, Error: err.Error()}
 	}
-	actualHash := hex.EncodeToString(hasher.Sum(make([]byte, 0, sha256.Size)))
+	actualHash := hex.EncodeToString(hasher.Sum(nil))
 	if actualHash != expectedHash {
 		return VerifyHashResponse{Success: true, Error: "hash mismatch"}
 	}
diff --git a/scenarios/verify.js b/scenarios/verify.js
index 9e8422a..6925dc5 100644
--- a/scenarios/verify.js
+++ b/scenarios/verify.js
@@ -39,11 +39,16 @@ if (__ENV.S3_ENDPOINTS) {
 // We will attempt to verify every object in "created" status. The scenario will execute
 // as many scenarios as there are objects. Each object will have 3 retries to be verified
 const obj_count_to_verify = obj_registry.getObjectCountInStatus("created");
+// Execute at least one iteration (shared-iterations can't run 0 iterations)
+const iterations = Math.max(1, obj_count_to_verify);
+// Executor shared-iterations requires number of iterations to be larger than number of VUs
+const vus = Math.min(__ENV.CLIENTS, iterations);
+
 const scenarios = {
     verify: {
         executor: 'shared-iterations',
-        vus: __ENV.CLIENTS,
-        iterations: obj_count_to_verify,
+        vus,
+        iterations,
         maxDuration: `${time_limit}s`,
         exec: 'obj_verify',
         gracefulStop: '5s',
@@ -51,7 +56,7 @@ const scenarios = {
 };
 
 export const options = {
-    scenarios: scenarios,
+    scenarios,
     setupTimeout: '5s',
 };