diff --git a/meta/scripts/lib/wic/plugins/source/bootimg-efi-isar.py b/meta/scripts/lib/wic/plugins/source/bootimg-efi-isar.py
index 6bc78d42..6c6698d6 100644
--- a/meta/scripts/lib/wic/plugins/source/bootimg-efi-isar.py
+++ b/meta/scripts/lib/wic/plugins/source/bootimg-efi-isar.py
@@ -104,7 +104,7 @@ class BootimgEFIPlugin(SourcePlugin):
                         (get_bitbake_var("KERNEL_IMAGETYPE"), get_bitbake_var("INITRAMFS_LINK_NAME"))

             label = source_params.get('label')
-            label_conf = "root=%s" % creator.rootdev
+            label_conf = f" root={creator.rootdev}" if creator.rootdev else ""
             if label:
                 label_conf = "LABEL=%s" % label

@@ -201,7 +201,8 @@ class BootimgEFIPlugin(SourcePlugin):
             boot_conf += "linux /%s\n" % kernel

             label = source_params.get('label')
-            label_conf = "LABEL=Boot root=%s" % creator.rootdev
+            label_conf = "LABEL=Boot"
+            label_conf += f" root={creator.rootdev}" if creator.rootdev else ""
             if label:
                 label_conf = "LABEL=%s" % label

@@ -366,7 +367,7 @@ class BootimgEFIPlugin(SourcePlugin):

             with tempfile.TemporaryDirectory() as tmp_dir:
                 label = source_params.get('label')
-                label_conf = "root=%s" % creator.rootdev
+                label_conf = f" root={creator.rootdev}" if creator.rootdev else ""
                 if label:
                     label_conf = "LABEL=%s" % label