diff --git a/rp2040/src/layout.rs b/rp2040/src/layout.rs
index 8b67f80..4749c28 100644
--- a/rp2040/src/layout.rs
+++ b/rp2040/src/layout.rs
@@ -13,7 +13,7 @@ pub enum ElrsButton {
     CH2 = 1,
     CH3 = 2,
     CH4 = 3,
-    CH5 = 4,
+    CH5 = 4, // AUX1/ARM
     CH6 = 5,
     CH7 = 6,
     CH8 = 7,