Application is not loading post DFU over serial

Question

Hello, 
 I am able to get a successful confirmation that my application has been updated using the nordic secure bootloader over serial code example. However, my application doesn't load. Here are the steps I followed: 
 1) Created an app package using cmd: nrfutil pkg generate --hw-version 52 --sd-req 0x00 --application-version 1 --application app.hex --key-file private.pem app52_1.zip 
 2) Erased the device and downloaded the bootloader (code based on \examples\dfu\secure_bootloader\pca10040_uart projoct. 
 3) Generated and programmed the setting.hex file 
 4) Recycled power and uploaded my app using cmd: nrfutil dfu serial -pkg app52_1.zip -p COM14 -fc 0. I got a confirmation message that the DFU is 100% done. 
 5) Recycled power but my app didn't load properly and neither did the bootloader. I know that because I cannot upload an app using step 3 anymore nor the correct DFU GPIO pattern is outputted. 
 
 Any ideas how to troubleshoot this issue? I did see other tickets referring to the boatload button being the issue so I disable that feature in the sdk_config.h file and still not working. I also tried to manually reset using nrfjprg --reset and that didn't help either. Any ideas? Thanks!

moose · Answer

So I finally was able to solve the problem. In short the documentation for the serial DFU bootlader with no softdevice is really missing few key steps. I would highly suggest they get updated. 
 Basically beside the application hex and the booloader hex you also need the mbr hex. This code that actually reside at memory address 0x0. It is already included in the softdevice but if you are not using a softdevice then you need to do few additional steps: 
 1) Add mbr_nrf52_2.4.1_mbr.hex. In segger you could do so under project options, debug, loader, additional load files. The relative path is ../../../../../../components/softdevice/mbr/hex/mbr_nrf52_2.4.1_mbr.hex 
 2) Add MBR_PRESENT to the preprocessor defines. In segger you could do so under project options, code, preprocessor, preprocessor definitions. 
 3) Include mbr and cmsis headers if they are not already included. In segger you could do so under project options, code, preprocessor, user include directories. The relatives file are 
 ../../../../../../components/softdevice/mbr/headers 
 ../../../../../../components/toolchain/cmsis/include 
 4) Change the flash start address to 0x1000 and update the size (substract 0x1000). I n segger you could do so under project options, code, linker, section placement macros. 
 5) Change the RAM start address to 0x20000010 and update the size (substract 0x10). In segger you could do so under project options, code, linker, section placement macros. 
 This worked for me. You could do the same changes plenty other ways but this is how I did it. Good luck!

Application is not loading post DFU over serial

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