From 3bd79d0328e651e55efe04d760a40e7963be225d Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Sat, 13 Sep 2025 01:08:31 +0800
Subject: [PATCH] make loader windows-friendly for usb serial

---
 loader/src/platform/cramium/usb/handlers.rs |  2 +-
 loader/src/platform/cramium/usb/mod.rs      | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/loader/src/platform/cramium/usb/handlers.rs b/loader/src/platform/cramium/usb/handlers.rs
index 992e609f9..8e4475916 100644
--- a/loader/src/platform/cramium/usb/handlers.rs
+++ b/loader/src/platform/cramium/usb/handlers.rs
@@ -159,7 +159,7 @@ pub fn get_descriptor_request(this: &mut CorigineUsb, value: u16, _index: usize,
     match (value >> 8) as u8 {
         USB_DT_DEVICE => {
             crate::println!("USB_DT_DEVICE");
-            let mut device_descriptor = DeviceDescriptor::default_composite();
+            let mut device_descriptor = DeviceDescriptor::composite_with_iad();
             device_descriptor.b_max_packet_size0 = 64;
 
             let len = length.min(core::mem::size_of::<DeviceDescriptor>());
diff --git a/loader/src/platform/cramium/usb/mod.rs b/loader/src/platform/cramium/usb/mod.rs
index 3ea51f151..71fe67342 100644
--- a/loader/src/platform/cramium/usb/mod.rs
+++ b/loader/src/platform/cramium/usb/mod.rs
@@ -168,6 +168,7 @@ impl DeviceDescriptor {
         }
     }
 
+    #[allow(dead_code)]
     pub fn default_composite() -> Self {
         Self {
             b_length: core::mem::size_of::<Self>() as u8,
@@ -186,6 +187,26 @@ impl DeviceDescriptor {
             b_num_configurations: 1,
         }
     }
+
+    // Windows-friendly composite: EF/02/01 indicates IAD-present composite
+    pub fn composite_with_iad() -> Self {
+        Self {
+            b_length: core::mem::size_of::<Self>() as u8,
+            b_descriptor_type: USB_DT_DEVICE,
+            b_cd_usb: 0x0200,
+            b_device_class: 0xEF,     // Miscellaneous
+            b_device_sub_class: 0x02, // Common Class
+            b_device_protocol: 0x01,  // Interface Association Descriptor (IAD)
+            b_max_packet_size0: 0x40,
+            id_vendor: VENDOR_ID,
+            id_product: PRODUCT_ID,
+            b_cd_device: 0x0101,
+            i_manufacturer: 0x01,
+            i_product: 0x02,
+            i_serial_number: 0x03,
+            b_num_configurations: 1,
+        }
+    }
 }
 impl AsRef<[u8]> for DeviceDescriptor {
     fn as_ref(&self) -> &[u8] {