Long Start Up Delay with DFU

[LukeC]

Hello,

I have a project that seems to have a very long start-up/boot delay before jumping to the Application when the DFU is added.

DFU is the BLE secure bootloader example project.  It uses the GPRET method of entry.

Both use the LF_SRC RC 

#define CLOCK_CONFIG_LF_SRC 0

No DFU Boot/Power-on Sequence:

Here is the the power on sequence with a project with no DFU, just application.  The yellow line is VDD and the blue line is a GPIO output.

App + DFU boot sequence: 


When I add in the DFU, there is a long 400ms delay.  The yellow line is VDD and the blue line is a GPIO output.

Question: Can you help me figure out how to minimize this DFU boot time? There must be some sort of setting that I have enabled that is delaying the bootloader entering into the application.

SDK: 16

Part: NRF52840

[Einar Thorsrud]

Hi,

This is surprisingly long. What kind of boot validation do you use for application and SoftDevice (none, CRC, SHA256, ECDSA)? Have you modified the bootloader in any way?