Please answer some questions below.
- “Application” and “SoftDevice” can be replaced by DFU, correct?
- Is Nordic DFU function inside “Module” (Orange colour part)?
- If question 2 is yes then the hardware flow control must be implemented by host right ?

Please answer some questions below.

Hi Nalin,
1. Correct
2. No, it's running on the application area. DFU function requires a bootloader. The bootloader is a special application that can run even before the softdevice and can execute the real application if there is no DFU needed.
We have a short presentation on how DFU works here: https://devzone.nordicsemi.com/b/blog/posts/a-presentation-on-how-nrf51-dfu-works
3. Which bootloader are you asking about ? UART DFU or BLE DFU ? If it's UART it's possible to do without hardware flow control but the bitrate should be low enough.
Hi Nalin,
1. Correct
2. No, it's running on the application area. DFU function requires a bootloader. The bootloader is a special application that can run even before the softdevice and can execute the real application if there is no DFU needed.
We have a short presentation on how DFU works here: https://devzone.nordicsemi.com/b/blog/posts/a-presentation-on-how-nrf51-dfu-works
3. Which bootloader are you asking about ? UART DFU or BLE DFU ? If it's UART it's possible to do without hardware flow control but the bitrate should be low enough.