pybricksdev.dfu: Fix not rebooting hub on Windows.

Fix not rebooting hub on Windows after flashing firmware by using
the dfu-util.exe fallback. The --reset option doesn't work on Windows
because WinUSB doesn't support it. Instead, we can use the --dfuse-address
option with ":leave" to exit DFU mode and reboot the device. This is
a bit simpler than creating a .dfu file anyway.

Fixes: #112

Author: dlech

CHANGELOG.md

@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Fixed USB/DFU hub not rebooting after flashing firmware on Windows (pybricksdev#112).
+
+[pybricksdev#112]: https://github.com/pybricks/pybricksdev/issues/112
+
 ## [2.1.0] - 2025-09-10
 
 ### Added

pybricksdev/dfu.py

@@ -225,20 +225,24 @@ def flash_dfu(firmware_bin: bytes, metadata: AnyFirmwareMetadata) -> None:
             # if libusb was not found, try using dfu-util command line tool
 
             with _get_dfu_util() as dfu_util:
-                dev_id = _get_vid_pid(dfu_util)
-
-                dfu_create.build(outfile, [[target]], dev_id)
+                with open(os.path.join(out_dir, "firmware.bin"), "wb") as bin_file:
+                    bin_file.write(firmware_bin)
 
                 exit(
                     call(
                         [
                             dfu_util,
                             "--device",
-                            f",{dev_id}",
+                            f",{_get_vid_pid(dfu_util)}",
                             "--alt",
                             "0",
+                            # We have to use dfuse option to be able to use
+                            # "leave" to exit DFU mode after flashing. --reset
+                            # doesn't work on Windows, so we can't use a .dfu file
+                            "--dfuse-address",
+                            f"{target['address']}:leave",
                             "--download",
-                            outfile,
+                            bin_file.name,
                         ]
                     )
                 )