diff --git a/src/device/pcsc.rs b/src/device/pcsc.rs
index 348bab5..bdbcd22 100644
--- a/src/device/pcsc.rs
+++ b/src/device/pcsc.rs
@@ -134,7 +134,7 @@ impl Device {
                 }
                 attribute
             })
-            .unwrap_or_else(|| "".to_string())
+            .unwrap_or_default()
     }
 }
 
diff --git a/src/firmware.rs b/src/firmware.rs
index 7bce386..9ffe5cb 100644
--- a/src/firmware.rs
+++ b/src/firmware.rs
@@ -26,10 +26,10 @@ impl Firmware {
     // pub fn verify(&self) -> Result<()> {
     // }
 
-    pub fn write_to<'a>(
+    pub fn write_to(
         &self,
         bootloader: &lpc55::Bootloader,
-        progress: Option<&'a dyn Fn(usize)>,
+        progress: Option<&dyn Fn(usize)>,
     ) {
         bootloader.receive_sb_file(&self.content, progress);
     }
diff --git a/src/pki/dev.rs b/src/pki/dev.rs
index c53dda5..5734abe 100644
--- a/src/pki/dev.rs
+++ b/src/pki/dev.rs
@@ -44,7 +44,7 @@ pub fn generate_selfsigned_fido() -> ([u8; 16], [u8; 36], String, rcgen::Certifi
     let key_pkcs8 = keypair.serialize_der();
     let key_pem = keypair.serialize_pem();
 
-    let key_info: p256::pkcs8::PrivateKeyInfo = key_pkcs8.as_slice().try_into().unwrap();
+    let key_info: pkcs8::PrivateKeyInfo = key_pkcs8.as_slice().try_into().unwrap();
     let secret_key: [u8; 32] = p256::SecretKey::try_from(key_info)
         .unwrap()
         .to_be_bytes()
diff --git a/src/transport/ctap.rs b/src/transport/ctap.rs
index 1c1b78c..e01154e 100644
--- a/src/transport/ctap.rs
+++ b/src/transport/ctap.rs
@@ -189,8 +189,7 @@ impl Device {
     pub fn call(&self, channel: Channel, request: Command) -> Result<Vec<u8>> {
         let result: Result<Vec<()>> = request
             .packets(channel)
-            .enumerate()
-            .map(|(_i, packet)| {
+            .map(|packet| {
                 // need to prefix report ID
                 let mut prefixed = vec![0];
                 prefixed.extend_from_slice(&packet);