diff --git a/poky/meta/classes/uboot-sign.bbclass b/poky/meta/classes/uboot-sign.bbclass
index 8beafff..de81ad1 100644
--- a/poky/meta/classes/uboot-sign.bbclass
+++ b/poky/meta/classes/uboot-sign.bbclass
@@ -116,7 +116,7 @@
 }
 
 python () {
-    if d.getVar('UBOOT_SIGN_ENABLE') == '1' and d.getVar('PN') == d.getVar('UBOOT_PN'):
+    if d.getVar('UBOOT_SIGN_ENABLE') == '1' and d.getVar('PN') == d.getVar('UBOOT_PN') and d.getVar('UBOOT_DTB_BINARY'):
         kernel_pn = d.getVar('PREFERRED_PROVIDER_virtual/kernel')
 
         # Make "bitbake u-boot -cdeploy" deploys the signed u-boot.dtb