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The Fast Device Firmware Update (Fast DFU) enables downloading the target firmware to a target device and enables the device to automatically check and update the firmware through Bluetooth transmission.

Compared with the over-the-air (OTA) technology which also enables downloading and updating the target firmware through Bluetooth transmission, GR551x Fast DFU greatly shortens the time for firmware update by providing Fast OTA Service which enables control, interaction, and various features of Fast DFU, as well as optimizing data read and write.

As a solution for wireless firmware update, Fast DFU features faster update process and better user experience. This document elaborates on principles and applications of Fast DFU for GR551x SoCs.

Before getting started, you can refer to the following documents.

Table 1 Reference documents
Name Description

GR551x Developer Guide

Introduces the software/hardware and quick start guide of GR551x SoCs.

Bluetooth Core Spec

Offers official Bluetooth standards and core specification from Bluetooth SIG.

J-Link/J-Trace User Guide

Provides J-Link operational instructions. Available at

Keil User Guide

Offers detailed Keil operational instructions. Available at

GR551x Bluetooth Low Energy Stack User Guide

Introduces the BLE Protocol Stack supported by GR551x SoCs.

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