diff --git a/sys/i386/acpica/genwakecode.sh b/sys/i386/acpica/genwakecode.sh
index e61f62cef4b6..caffbf8642ae 100644
--- a/sys/i386/acpica/genwakecode.sh
+++ b/sys/i386/acpica/genwakecode.sh
@@ -3,7 +3,7 @@
 #
 file2c 'static char wakecode[] = {' '};' <acpi_wakecode.bin
 
-nm -n acpi_wakecode.o | while read offset dummy what
+nm -n --defined-only acpi_wakecode.o | while read offset dummy what
 do
     echo "#define ${what}	0x${offset}"
 done