RE: Problem with flash overflow when adding BLE DFU on nRF52833

zciwor — Mon, 09 Jun 2025 13:17:42 GMT

This is very helpful. I will experiment with this. Thank you!

RE: Problem with flash overflow when adding BLE DFU on nRF52833

Vidar Berg — Sat, 07 Jun 2025 05:54:00 GMT

Hello,

The size of the application region is significantly reduced when MCUBoot is enabled in the build. To get the size that will be available to the app, you must first subtract the size of the bootloader (48kB by default)) from the 488 kB currently available to your app. Then, divide the remaining space by 2. This gives you the size of the MCUBoot primary and secondary slot. So, the new application region (mcuboot primary) size = (488k - 48k ) / 2 = 220 kB, and your current app size is 241768 bytes = 236.1 kB.

Example of a typical memory layout on the nRF52833

But we can halve the bootloader footprint by overwriting the default MCUBoot build configuration and disable logging and other things we don't need. To overwrite the default configuration we can create a folder named 'sysbuild' in the project root with the following folder structure:

<project directory>/
├── sysbuild/
│ └── mcuboot/
│ └── prj.conf

Below is an example configuration you can try with. The bootloader region is set to 24kB in this configuration. After adding the sysbuild folder to the project, remember to do a 'pristine' build to alllow the build system to detect that the new configuration files have been added.

devzone.nordicsemi.com/.../1638.sysbuild.zip

Best regards,

Vidar