diff --git a/src/backends/yubideck_v3.rs b/src/backends/yubideck_v3.rs
index 8984011..1bbfaa4 100644
--- a/src/backends/yubideck_v3.rs
+++ b/src/backends/yubideck_v3.rs
@@ -2,6 +2,9 @@
 //! USB device: 1973:2001
 //!
 //! USB interface: 0
+//! 
+//! Note that carding in using the YubiDeck card reader will not
+//! work until a compatible `aimeio` implementation is provided.
 //!
 //! ## Protocol information
 //!