diff --git a/card-functionality/src/cards.rs b/card-functionality/src/cards.rs
index c6e0271..4f6c0a8 100644
--- a/card-functionality/src/cards.rs
+++ b/card-functionality/src/cards.rs
@@ -104,7 +104,7 @@ impl TestCard {
                     let ard = ca.get_application_related_data()?;
                     let app_id = ard.get_application_id()?;
 
-                    if app_id.ident().as_str() == ident {
+                    if app_id.ident().as_str() == ident.to_uppercase() {
                         ca.init_caps(&ard)?;
 
                         // println!("opened pcsc card {}", ident);
diff --git a/openpgp-card/src/card_do/application_id.rs b/openpgp-card/src/card_do/application_id.rs
index 9fe7dc5..0be8cf4 100644
--- a/openpgp-card/src/card_do/application_id.rs
+++ b/openpgp-card/src/card_do/application_id.rs
@@ -57,7 +57,8 @@ impl ApplicationIdentifier {
     }
 
     /// This ident is constructed as the concatenation of manufacturer
-    /// id, a colon, and the card serial (in hexadecimal representation).
+    /// id, a colon, and the card serial (in hexadecimal representation,
+    /// with uppercase hex digits).
     ///
     /// It is a more easily human-readable, shorter form of the full
     /// 16-byte AID ("Application Identifier").