diff --git a/layers/meta-belden-coreos/lib/devtool/coreos-efibootguard.py b/layers/meta-belden-coreos/lib/devtool/coreos-efibootguard.py
index 120e66d..6dbceb3 100644
--- a/layers/meta-belden-coreos/lib/devtool/coreos-efibootguard.py
+++ b/layers/meta-belden-coreos/lib/devtool/coreos-efibootguard.py
@@ -218,12 +218,15 @@ def dtb_to_list(dtb, deploy_dir) -> list[str]:
     Convert the string array from bitbake into a python list. Only the basename
     of the dtb is taken and DEPLOY_DIR is appended
     """
-    return list(
-        map(
-            lambda s: os.path.join(deploy_dir, os.path.basename(s)),
-            filter(lambda s: s.strip() != "", dtb.split(" ")),
+    if dtb:
+        return list(
+            map(
+                lambda s: os.path.join(deploy_dir, os.path.basename(s)),
+                filter(lambda s: s.strip() != "", dtb.split(" ")),
+            )
         )
-    )
+    else:
+        return []
 
 
 def efibootguard_generate_uki(args, config, basepath, workspace):