OTA and DFU¶

DFU v2 is the SiFli-SDK firmware-update middleware for DFU and OTA workflows. It provides three transport channels: USB-CDC, BLE, and Bluetooth PAN. Each channel includes a user application and a matching loader subproject.

Start by selecting the transport that matches the product's update path. Then begin with the corresponding application example; its loader is brought into the build automatically.

DFU v2 Structure¶

Figure: DFU v2 example structure

dfu_v2/
├── cdc/       USB-CDC channel
│   ├── app/       User application and PC update tool
│   └── loader/    CDC DFU loader
├── ble/       BLE channel
│   ├── app/       BLE peripheral application
│   └── loader/    BLE DFU loader
└── bt_pan/    Bluetooth PAN channel
    ├── app/       Application that downloads firmware from a server
    └── loader/    PAN DFU loader

The application and loader for a given channel are designed to be used together. When you build an application, the SDK uses the AddDFU_* logic in building.py to include the matching loader as a subproject; do not build that loader separately. For BLE, the application supports runtime updates, while an update to the HCPU itself completes through the loader.

Choose an Update Channel¶

Table: DFU v2 transport selection

Channel	Documented update path	Typical fit
USB-CDC	A PC updates the device through a USB virtual serial port.	Production, lab, and wired service workflows.
BLE	A BLE peripheral application receives an update.	A mobile app updates a connected product.
Bluetooth PAN	The device uses Bluetooth PAN networking to download an update from an HTTP server.	Connected products that retrieve their own update image.

Product Update Review¶

The selected transport matches the product's available connection path.
The application and matching loader are built and tested as one update flow.
The supported target board is confirmed in that example's README.
Update interruption, recovery, and factory-service behavior are defined for the product.
Image authenticity, integrity, version policy, and partition capacity are reviewed for the product release.
Failed-update logs can be collected without depending on a healthy application.

Build a DFU v2 Example¶

From an example's project/ directory, build with:

scons --board=<board-name> -j8

Each example README lists its supported boards. The DFU v2 middleware configuration itself is under middleware/dfu_v2 in SiFli-SDK.

DFU v2 SDK Examples¶

Table: Official SiFli-SDK DFU v2 examples for SF32LB58x

Channel	User application	Loader subproject
USB-CDC	`cdc/app`	`cdc/loader`
BLE	`ble/app`	`ble/loader`
Bluetooth PAN	`bt_pan/app`	`bt_pan/loader`

For the complete source index and current SDK navigation, see DFU v2 examples in SiFli-SDK.