Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Menon — Tue, 30 Sep 2025 06:42:34 GMT

Hello,

Sorry for getting back to you a bit late on this. I had to finish some other tasks last week and only worked limited hours, which caused the delay in responding. Have you been able to make any progress on this issue?

[quote user="Jacob W"]CONFIG_FLASH_SIZE in the partition or ${${image_name}_CONFIG_FLASH_SIZE}, it seems to be empty. When I'm building with --no-sysbuild parameter, in the build/zephyr/.config file there is a parameter CONFIG_FLASH_SIZE=1024. I'm not changing this value anywhere in my config files as it should not be changed in the project .conf file, right? Where is it taken from?[/quote]

It’s not recommended to modify this config value. It’s not taken from prj.conf; instead, it is derived from the devicetree. The property zephyr,flash in the /chosen node refers to the flash device node, and its reg property is used to set the defaults for both CONFIG_FLASH_BASE_ADDRESS and CONFIG_FLASH_SIZE Kconfig options. See the Zephyr-specific /chosen node. Do you have any overlay which touches the flash? Check the overlays for both the application and MCUboot.

Kind Regards,

Abhijith

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Jacob W — Thu, 18 Sep 2025 15:57:44 GMT

Hi, just an additional note to clear that out - in case of failed build (with partition_manager error) the .config file in the build/zephyr directory is not created at all, therefore to check it's value I had to print it in the partition_manager CMake script.

Best regards,
Jacob

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Jacob W — Thu, 18 Sep 2025 12:58:00 GMT

Hi, I have checked this and this could be (probably indirect) reason for this issue, when I'm adding the log to print the CONFIG_FLASH_SIZE in the partition or ${${image_name}_CONFIG_FLASH_SIZE}, it seems to be empty. When I'm building with --no-sysbuild parameter, in the build/zephyr/.config file there is a parameter CONFIG_FLASH_SIZE=1024. I'm not changing this value anywhere in my config files as it should not be changed in the project .conf file, right? Where is it taken from?

I'm using the nRF9151 DK board, but I could not find this config parameter anywhere in the config files for this board in the SDK files (there is FLASH_LOAD_SIZE, but not FLASH_SIZE)

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Menon — Thu, 18 Sep 2025 11:25:51 GMT

Hello,

I was checking the math() function inside the CMake documentation to get a clearer picture. Could this be due to the value assigned to CONFIG_FLASH_SIZE?
Could you check the build directory to see what value is being assigned?

Kind regards,
Abhijith

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Jacob W — Mon, 15 Sep 2025 14:58:09 GMT

Hi,

I'm sorry for a late reply. I was trying both ways, also without defining static partition file (and expecting to have one generated in the build directory), but it's failing on the same step. Based on reading the logs it seems to be failing on this line from the partition_manager.cmake in this line:

math(EXPR flash_size "${${image_name}_CONFIG_FLASH_SIZE} * 1024" OUTPUT_FORMAT HEXADECIMAL)

(the error: 'math cannot parse the expression: " * 1024": syntax error, unexpected'). So it seems as if it cannot evaluate variable: '${${image_name}_CONFIG_FLASH_SIZE}', but I don't know why.

I have noticed that in case of Blinky sample (which I am able to build using sysbuild) the build starts with running the CMake for mcuboot, and later with CMake for the project (Blinky). In my case (in which I'm getting the partition_manager issue) it starts at once with running the CMake for the project. I'm pointing this out since I'm not sure if this might not be something that makes the difference.

Could you advise what could be the possible reason for this issue?

Best regards,
Jacob

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Menon — Tue, 02 Sep 2025 09:12:12 GMT

Hello,

I’m not sure what the cause of the issue you’re seeing is. The files you’ve shared look fine to me, and I don’t think they would be the source of the problem. What I would recommend is to try building the application without defining a pm_static file. This will generate a dynamic partition file inside the build folder. You can use that as a reference and, based on it, create a static partition file to see if that resolves the issue.

If you can share the generated partition file, I would be happy to take a look.

Kind regards,
Abhijith

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Jacob W — Thu, 28 Aug 2025 09:49:16 GMT

Hello,

thank you for your reply. I'm building for nRF9151 DK. In the attachment I have added the config files and overlay. Please please let me know if you would need anything else.

I have checked the Academy course, but based on that it seemed that the steps I have made should be enough (at least to compile), but in case of my project for some reason enabling the sysbuild triggers this problem with partition manager

Best regards,
Jacob
devzone.nordicsemi.com/.../07350.prj.conf devzone.nordicsemi.com/.../1411.app.overlay devzone.nordicsemi.com/.../7367.sysbuild.conf

RE: Build failing with sysbuild enabled (math cannot parse the expression: " * 1024")

Menon — Thu, 28 Aug 2025 08:55:28 GMT

Hello,

Could you share some more information, such as the build configuration you are using? Are you building for a DK or for your custom board? I don’t think this issue is related to MCUboot.

You can also take a look at this Academy course, which shows how to add DFU support to the application.

Kind regards,
Abhijith