Editing USB (section)

=== Device Firmware Upgrade mechanism <span class="anchor" id="DFU"></span>===
''Device Firmware Upgrade'' (DFU) is a generic mechanism for upgrading the [[firmware]] of USB devices with improved versions provided by their manufacturers, offering (for example) a way to deploy firmware bug fixes. During the firmware upgrade operation, USB devices change their operating mode effectively becoming a [[Programmable read-only memory|PROM]] programmer. Any class of USB device can implement this capability by following the official DFU specifications. Doing so allows use of DFU-compatible host tools to update the device.<ref name="dfu-1.1"/><ref name="dfu-1.0">{{cite web
 | url = http://www.usb.org/developers/devclass_docs/usbdfu10.pdf
 | archive-url = https://web.archive.org/web/20140824054756/http://www.usb.org/developers/devclass_docs/usbdfu10.pdf
 | title = Universal Serial Bus Device Class Specification for Device Firmware Upgrade, Version 1.0
 | date = 13 May 1999 | access-date = 8 September 2014 | archive-date = 24 August 2014
 | publisher = USB Implementers Forum
 | pages = 7–8
}}</ref><ref>{{cite web
 | url = https://admin.fedoraproject.org/pkgdb/package/dfu-util/
 | title = rpms/dfu-util: USB Device Firmware Upgrade tool
 | date = 14 May 2014
 | access-date = 8 September 2014
 | website = fedoraproject.org
 | archive-date = 8 September 2014
| archive-url = https://web.archive.org/web/20140908112041/https://admin.fedoraproject.org/pkgdb/package/dfu-util/
 | url-status = live
 }}</ref>

DFU is sometimes used as a flash memory programming protocol in microcontrollers with built-in USB bootloader functionality.
<ref>{{cite web
 | url = https://www.st.com/resource/en/application_note/cd00264379-usb-dfu-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf
 | title = AN3156: USB DFU protocol used in the STM32 bootloader
 | date = 7 February 2023
 | access-date = 28 January 2024
 | website = st.com
 }}</ref>