Fix reset from ui

rust/serial_reader/src/main.rs

@@ -73,6 +73,8 @@ fn main() {
                     }
                 }
 
+                drop(port_lock);
+
                 thread::sleep(Duration::from_millis(10));
             }
         });

rust/serial_reader/src/port.rs

@@ -69,7 +69,7 @@ impl Port {
     }
 
     fn loop_usb_devices(usb_device: UsbId) -> Result<String> {
-        loop {
+        for _ in 0..3 {
             if let Some(device) = Self::find_macroboard(&usb_device)? {
                 return Ok(device);
             }
@@ -81,6 +81,8 @@ impl Port {
 
             std::thread::sleep(Duration::from_secs(2));
         }
+
+        Err(anyhow!("no device found"))
     }
 
     fn find_macroboard(usb_device: &UsbId) -> Result<Option<String>> {