diff --git a/libsel4debug/include/sel4debug/debug.h b/libsel4debug/include/sel4debug/debug.h
index 8803f8b..ad0f2bc 100644
--- a/libsel4debug/include/sel4debug/debug.h
+++ b/libsel4debug/include/sel4debug/debug.h
@@ -21,6 +21,7 @@
 
 void debug_cap_identify(seL4_CPtr cap);
 
+#ifdef CONFIG_DEBUG_BUILD
 static inline int debug_cap_is_valid(seL4_CPtr cap)
 {
     return (0 != seL4_DebugCapIdentify(cap));
@@ -39,7 +40,7 @@
     // cap_notification_cap = 6, but we can't include it here
     return (6 == seL4_DebugCapIdentify(cap));
 }
-
+#endif /* CONFIG_DEBUG_BUILD */
 
 void debug_print_bootinfo(seL4_BootInfo *info);