diff --git a/conf/machine/include/omap-a15.inc b/conf/machine/include/omap-a15.inc
index 02225a4e..4f57e6d1 100644
--- a/conf/machine/include/omap-a15.inc
+++ b/conf/machine/include/omap-a15.inc
@@ -19,7 +19,7 @@ UBOOT_ARCH = "arm"
 UBOOT_ENTRYPOINT = "0x80008000"
 UBOOT_LOADADDRESS = "0x80008000"
 
-DEVICETREE_FILE = "${@d.getVar('KERNEL_DEVICETREE').replace("ti/","")}"
+DEVICETREE_FILE = "${@(d.getVar('KERNEL_DEVICETREE') or "").replace("ti/","")}"
 
 # Generate an extlinux.conf file
 UBOOT_EXTLINUX = "1"