diff --git a/toolkit/tools/imagegen/diskutils/diskutils.go b/toolkit/tools/imagegen/diskutils/diskutils.go
index 5e441206b4c..0beab227883 100644
--- a/toolkit/tools/imagegen/diskutils/diskutils.go
+++ b/toolkit/tools/imagegen/diskutils/diskutils.go
@@ -492,7 +492,7 @@ func CreatePartitions(diskDevPath string, disk configuration.Disk, rootEncryptio
 			return partDevPathMap, partIDToFsTypeMap, encryptedRoot, readOnlyRoot, err
 		}
 
-		partFsType, err := FormatSinglePartition(partDevPath, partition)
+		partFsType, err := formatSinglePartition(diskDevPath, partDevPath, partition)
 		if err != nil {
 			err = fmt.Errorf("failed to format partition:\n%w", err)
 			return partDevPathMap, partIDToFsTypeMap, encryptedRoot, readOnlyRoot, err
@@ -782,12 +782,13 @@ func setGptPartitionType(partition configuration.Partition, timeoutInSeconds, di
 	return
 }
 
-// FormatSinglePartition formats the given partition to the type specified in the partition configuration
-func FormatSinglePartition(partDevPath string, partition configuration.Partition,
+// formatSinglePartition formats the given partition to the type specified in the partition configuration
+func formatSinglePartition(diskDevPath string, partDevPath string, partition configuration.Partition,
 ) (fsType string, err error) {
 	const (
-		totalAttempts = 5
-		retryDuration = time.Second
+		totalAttempts    = 5
+		retryDuration    = time.Second
+		timeoutInSeconds = "5"
 	)
 
 	fsType = partition.FsType
@@ -803,14 +804,14 @@ func FormatSinglePartition(partDevPath string, partition configuration.Partition
 			fsType = "vfat"
 		}
 
-		mkfsArgs := []string{"-t", fsType}
+		mkfsArgs := []string{"--timeout", timeoutInSeconds, diskDevPath, "mkfs", "-t", fsType}
 		mkfsArgs = append(mkfsArgs, mkfsOptions...)
 		mkfsArgs = append(mkfsArgs, partDevPath)
 
 		err = retry.Run(func() error {
-			_, stderr, err := shell.Execute("mkfs", mkfsArgs...)
+			_, stderr, err := shell.Execute("flock", mkfsArgs...)
 			if err != nil {
-				logger.Log.Warnf("Failed to format partition using mkfs: %v", stderr)
+				logger.Log.Warnf("Failed to format partition using mkfs (and flock): %v", stderr)
 				return err
 			}
 
diff --git a/toolkit/tools/pkg/imagecustomizerlib/shrinkfilesystems.go b/toolkit/tools/pkg/imagecustomizerlib/shrinkfilesystems.go
index aa058dcf422..f444de5a1b1 100644
--- a/toolkit/tools/pkg/imagecustomizerlib/shrinkfilesystems.go
+++ b/toolkit/tools/pkg/imagecustomizerlib/shrinkfilesystems.go
@@ -85,9 +85,10 @@ func shrinkFilesystems(imageLoopDevice string, verityHashPartition *imagecustomi
 		}
 
 		// Shrink the file system with resize2fs -M
-		stdout, stderr, err := shell.Execute("resize2fs", "-M", partitionLoopDevice)
+		stdout, stderr, err := shell.Execute("flock", "--timeout", "5", imageLoopDevice,
+			"resize2fs", "-M", partitionLoopDevice)
 		if err != nil {
-			return fmt.Errorf("failed to resize %s with resize2fs:\n%v", partitionLoopDevice, stderr)
+			return fmt.Errorf("failed to resize %s with resize2fs (and flock):\n%v", partitionLoopDevice, stderr)
 		}
 
 		// Find the new partition end value
@@ -103,10 +104,11 @@ func shrinkFilesystems(imageLoopDevice string, verityHashPartition *imagecustomi
 		}
 
 		// Resize the partition with parted resizepart
-		_, stderr, err = shell.ExecuteWithStdin("yes" /*stdin*/, "parted", "---pretend-input-tty",
-			imageLoopDevice, "resizepart", strconv.Itoa(partitionNumber), end)
+		_, stderr, err = shell.ExecuteWithStdin("yes" /*stdin*/, "flock", "--timeout", "5", imageLoopDevice,
+			"parted", "---pretend-input-tty", imageLoopDevice, "resizepart",
+			strconv.Itoa(partitionNumber), end)
 		if err != nil {
-			return fmt.Errorf("failed to resizepart %s with parted:\n%v", partitionLoopDevice, stderr)
+			return fmt.Errorf("failed to resizepart %s with parted (and flock):\n%v", partitionLoopDevice, stderr)
 		}
 
 		// Re-read the partition table