--- zzzz-none-000/linux-4.9.279/drivers/of/unittest-data/Makefile	2021-08-08 06:38:54.000000000 +0000
+++ puma7-atom-6591-750/linux-4.9.279/drivers/of/unittest-data/Makefile	2023-02-08 11:43:42.000000000 +0000
@@ -1,7 +1,17 @@
 obj-y += testcases.dtb.o
 
-targets += testcases.dtb testcases.dtb.S
+# enable creation of __symbols__ node
+DTC_FLAGS_overlay += -@
+DTC_FLAGS_overlay_bad_phandle += -@
+DTC_FLAGS_overlay_bad_symbol += -@
+DTC_FLAGS_overlay_base += -@
+DTC_FLAGS_testcases += -@
+
+# suppress warnings about intentional errors
+DTC_FLAGS_testcases += -Wno-interrupts_property
 
-.SECONDARY: \
-	$(obj)/testcases.dtb.S \
-	$(obj)/testcases.dtb
+.PRECIOUS: \
+	$(obj)/%.dtb.S \
+	$(obj)/%.dtb
+
+targets += testcases.dtb testcases.dtb.S