Introduction
CFU is a protocol from Microsoft to make it easy to install firmware on HID devices.
This protocol is unique in that it requires has a pre-download phase before sending the firmware to the microcontroller. This is so the device can check if the firmware is required and compatible. CFU also requires devices to be able to transfer the entire new transfer mode in runtime mode.
See https://docs.microsoft.com/en-us/windows-hardware/drivers/cfu/cfu-specification for more details.
This plugin supports the following protocol ID:
com.microsoft.cfu
GUID Generation
These devices use standard USB DeviceInstanceId values, as well as two extra for the component ID and the bank, e.g.
HIDRAW\VEN_17EF&DEV_7226&CID_01&BANK_1HIDRAW\VEN_17EF&DEV_7226&CID_01HIDRAW\VEN_17EF&DEV_7226
Update Behavior
The device has to support runtime updates and does not have a detach-into-bootloader mode — but after the install has completed the device still has to reboot into the new firmware.
Vendor ID Security
The vendor ID is set from the USB vendor, in this instance set to HIDRAW:0x17EF
External Interface Access
This plugin requires read/write access to /dev/bus/usb.