NCS/Zephyr/MCUBoot - Image too large for flash region

[Christian Holland]

Hi,

I've recently updated to the latest NCS repo. I'm not entirely sure what version of NCS i was on before (perhaps if you could tell me how to check - as i made a copy of that entire directory before updating), but I was on Zephyr 2.3.0 and I'm now on 2.3.99.

When building my image before, the image was too big for the flash region, but I was able to change MCUBoot's prj.conf to include: CONFIG_BOOT_SWAP_USING_MOVE=y. This then allowed my image to fit in because there was no swap partition. This was the rom_report for my image on the previous version:

[2/2] Running utility command for rom_report
Partition Manager report
FLASH (0x80000):
+-----------------------------------------+
| 0x0: mcuboot (0x98f0)                   |
| 0x98f0: EMPTY_0 (0x710)                 |
+---0xa000: mcuboot_primary (0x29000)-----+
| 0xa000: mcuboot_pad (0x200)             |
+---0xa200: mcuboot_primary_app (0x28e00)-+
| 0xa200: app (0x28e00)                   |
| 0x33000: mcuboot_scratch (0x1e000)      |
| 0x51000: mcuboot_secondary (0x29000)    |
| 0x7a000: littlefs_storage (0x6000)      |
+-----------------------------------------+


After upgrading and building the same project, I now get the following error:

Memory region         Used Size  Region Size  %age Used

           FLASH:      270804 B     212480 B    127.45%

            SRAM:       50696 B        64 KB     77.36%

        IDT_LIST:         216 B         2 KB     10.55/home/chris/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/9.2.0/../../../../arm-zephyr-eabi/bin/ld: zephyr/zephyr_prebuilt.elf section `text' will not fit in region `FLASH'

/home/chris/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/9.2.0/../../../../arm-zephyr-eabi/bin/ld: region `FLASH' overflowed by 58324 bytes

Could you please tell me what I can do to make this work like on the old version?

[Christian Holland]

it seems like the amount of space allowed for the entire flash region has shrunk after I've upgraded. This is the build output on the older version of NCS:

Memory region         Used Size  Region Size  %age Used

           FLASH:      203836 B     224768 B     90.69%

            SRAM:       38232 B        64 KB     58.34%

        IDT_LIST:         200 B         2 KB      9.77%

Notice the region size - the builds fine. The region size on my original post (later version) is 212480, lower than above. Not sure how I've lost this allocated space? 
I have checked, and MCUBoot has increased in size by 2kb from the older version. This doesn't explain the difference in region size though...

[Sigurd]

Hi,

It's the Partition Manager that handles the flash partitions. By default, the Partition Manager dynamically places the partitions in memory. See the documentation for the Partition Manager here.

Christian Holland said:

Not sure how I've lost this allocated space? 

Take a look at the Partition Manager yml and config files in your build folder to see how the space is allocated.