diff --git a/usb/src/dev_handler.rs b/usb/src/dev_handler.rs
index bc17e0c..149b3a8 100644
--- a/usb/src/dev_handler.rs
+++ b/usb/src/dev_handler.rs
@@ -5,12 +5,12 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::time::Duration;
 use async_trait::async_trait;
 use log::{debug, error, info, trace};
-use rusb::{Direction, UsbContext};
+use rusb::Direction;
 use tokio::sync::mpsc;
 use pod_core::midi_io::{MidiIn, MidiOut};
 use crate::devices::UsbDevice;
 use crate::endpoint::{Endpoint, find_endpoint};
-use crate::framer::{BoxedInFramer, BoxedOutFramer, InFramer};
+use crate::framer::{BoxedInFramer, BoxedOutFramer};
 use crate::line6::line6_read_serial;
 use crate::midi_framer::new_usb_midi_framer;
 use crate::podxt_framer::new_pod_xt_framer;
@@ -51,14 +51,6 @@ pub struct DeviceOutput {
     inner: Arc<DeviceInner>
 }
 
-pub struct DevHandler {
-    handle: Arc<DeviceHandle>,
-    read_ep: Endpoint,
-    write_ep: Endpoint,
-    tx: mpsc::UnboundedSender<Vec<u8>>,
-    rx: mpsc::UnboundedReceiver<Vec<u8>>
-}
-
 const READ_DURATION: Duration = Duration::from_millis(10 * 1000);
 const WRITE_DURATION: Duration = Duration::from_millis(10 * 1000);
 
diff --git a/usb/src/lib.rs b/usb/src/lib.rs
index 73737b8..60ac730 100644
--- a/usb/src/lib.rs
+++ b/usb/src/lib.rs
@@ -246,7 +246,7 @@ pub fn usb_device_for_address(dev_addr: &str) -> Result<(impl MidiIn, impl MidiO
     let port_n_re = Regex::new(r"\d+").unwrap();
     let port_id_re = Regex::new(r"\d+:\d+").unwrap();
 
-    let mut found;
+    let found;
     if port_id_re.is_match(dev_addr) {
         found = devices.get_mut(dev_addr);
     } else if port_n_re.is_match(dev_addr) {
diff --git a/usb/src/midi_framer.rs b/usb/src/midi_framer.rs
index 984b525..45cd333 100644
--- a/usb/src/midi_framer.rs
+++ b/usb/src/midi_framer.rs
@@ -31,7 +31,7 @@ impl InFramer for UsbMidiInFramer {
         let mut ret = vec![];
         bytes.chunks_exact(4).for_each(|b| {
             let mut push_sysex = false;
-            let mut sysex_ptr = &mut self.sysex_buffer[self.sysex_offset .. self.sysex_offset + 3];
+            let sysex_ptr = &mut self.sysex_buffer[self.sysex_offset .. self.sysex_offset + 3];
             match b[0] {
                 0x0b => ret.push( b[1 .. 4].to_vec() ),
                 0x0c => ret.push( b[1 .. 3].to_vec() ),
diff --git a/usb/src/podxt_framer.rs b/usb/src/podxt_framer.rs
index 404b293..2d05cb5 100644
--- a/usb/src/podxt_framer.rs
+++ b/usb/src/podxt_framer.rs
@@ -46,13 +46,13 @@ impl PodXtInFramer {
 impl InFramer for PodXtInFramer {
     fn decode_incoming(&mut self, bytes: &[u8]) -> Vec<Vec<u8>> {
         // add received data to the read buffer at current read offset
-        let mut read_ptr = &mut self.read_buffer[self.read_offset .. self.read_offset + bytes.len()];
+        let read_ptr = &mut self.read_buffer[self.read_offset .. self.read_offset + bytes.len()];
         read_ptr.copy_from_slice(bytes);
 
         // go through the whole receive buffer from offset 0, check for
         // for messages as send them to the MIDI thread
         let process_len = self.read_offset + read_ptr.len();
-        let mut process_buf = self.read_buffer[..process_len].as_mut();
+        let process_buf = self.read_buffer[..process_len].as_mut();
         let mut process_offset = 0;
         let mut ret = vec![];
         loop {
diff --git a/usb/src/usb.rs b/usb/src/usb.rs
index 9a023a1..a498c0a 100644
--- a/usb/src/usb.rs
+++ b/usb/src/usb.rs
@@ -9,7 +9,7 @@ use std::thread;
 use std::time::Duration;
 use log::{debug, error, info};
 use rusb::{Context, Hotplug, HotplugBuilder, Registration, UsbContext};
-use rusb::constants::{LIBUSB_ENDPOINT_DIR_MASK, LIBUSB_ENDPOINT_IN, LIBUSB_ENDPOINT_OUT, LIBUSB_ERROR_INTERRUPTED, LIBUSB_TRANSFER_CANCELLED, LIBUSB_TRANSFER_TYPE_BULK};
+use rusb::constants::{LIBUSB_ENDPOINT_DIR_MASK, LIBUSB_ENDPOINT_IN, LIBUSB_ENDPOINT_OUT, LIBUSB_TRANSFER_TYPE_BULK};
 use rusb::ffi::{libusb_alloc_transfer, libusb_cancel_transfer, libusb_free_transfer, libusb_submit_transfer, libusb_transfer};
 use crate::check;
 use crate::util::usb_address_string;
@@ -390,7 +390,7 @@ pub mod libusb {
     }
 
     /// Resets the specified device handle.
-    pub(super) fn reset<T: UsbContext>(mut hdl: DeviceHandle<T>) -> rusb::Result<DeviceHandle<T>> {
+    pub(super) fn reset<T: UsbContext>(hdl: DeviceHandle<T>) -> rusb::Result<DeviceHandle<T>> {
         let dev = hdl.device();
         let port = dev.port_numbers()?;
         // WinUSB API with libusbK driver requires interface 0 to be claimed in