diff --git a/src/types/usb_device.rs b/src/types/usb_device.rs
index e80a7c4..fdccbf3 100644
--- a/src/types/usb_device.rs
+++ b/src/types/usb_device.rs
@@ -14,7 +14,7 @@ use usb_device::{
 #[derive(Default, Copy, Clone)]
 pub(crate) struct USBEndpoint {
     is_allocated: bool,
-    size: u16,
+    size: u8,
     ep_type: u8,
     ep_dir: bool,
     banks: u8,
@@ -46,7 +46,16 @@ impl USBEndpoint {
 
     #[inline]
     fn set_size(&mut self, size: u16) {
-        self.size = size;
+        self.size = match size {
+            8 => 0b000,
+            16 => 0b001,
+            32 => 0b010,
+            64 => 0b011,
+            128 => 0b100,
+            256 => 0b101,
+            512 => 0b110,
+            _ => unreachable!(),
+        }
     }
 }