nRF5340 net core flash partition

[Jason]

Hi:

My project has multi-image(mcuboot, cpuapp, b0n, cpunet), and now I am encountering the issue that the net core flash overflow.

ld.exe: region `FLASH' overflowed by 10609 bytes

According to the build log, the b0n size is only 21020 bytes, but its Region Size is 34304 bytes.

So I would like to reduce the b0n Region size to fix this issue. I know to place a pm_static.yml in the boards folder can custom the application core flash partition, but this does not work for the net core when I place a pm_static_net.yml in the child_image/hci_rpmsg/boards/ folder. ( the partitions_CPUNET.yml in the build/hci_rpmsg folder is still not changed)

I have two questions.

1. how to custom the net core flash partition in vs code?

2. is possible to optimize the size of b0n and net core application?

Thanks!

[Vidar Berg]

Hello,

The easiest solution is probably to build the netcore bootloader with the overlay configuration already provided in the sample: https://github.com/nrfconnect/sdk-nrf/blob/0ebb59dbe0084b53d85f7935e2e236ce83e084b4/samples/nrf5340/netboot/overlay-minimal-size.conf 

To select the overlay, you can pass '-Dhci_rpmsg_b0n_OVERLAY_CONFIG=overlay-minimal-size.conf' to the CMake build. 

In VS code:

 

Or from the command line:

$ west build -b nrf5340dk_nrf5340_cpuapp --pristine -- -Dhci_rpmsg_b0n_OVERLAY_CONFIG=overlay-minimal-size.conf

Best regards,

Vidar