1 files changed, 9 insertions, 0 deletions
diff --git a/src/common/tusb_debug.h b/src/common/tusb_debug.h
index 470a8a18b..ba5b4afd1 100644
--- a/src/common/tusb_debug.h
+++ b/src/common/tusb_debug.h
@@ -117,7 +117,16 @@ static inline const char* tu_lookup_find(tu_lookup_table_t const* p_table, uint3
     }
   }
 
+  #ifndef CFG_TUSB_DEBUG_PRINTF
+  // not found return the key value in hex if no custom printf is defined
+  static char not_found[11];
+  if (snprintf(not_found, sizeof(not_found), "0x%08lX", (unsigned long)key) <= 0) {
+    not_found[0] = 0;
+  }
+  return not_found;
+  #else
   return "NotFound";
+  #endif
 }
 
 #endif // CFG_TUSB_DEBUG