nrf_audio sample with FOTA enabled exceeds ipc_radio FLASH partition

[Benno Trutmann]

Hi.

I try to build the nrf_audio sample as BIS headset with enabled FOTA and NCS2.7.0 and get the following link error for the ipc_radio image:

FAILED: zephyr/zephyr_pre0.elf zephyr/zephyr_pre0.map nrf5340_audio/build/sink-fota/ipc_radio/zephyr/zephyr_pre0.map
ld.bfd.exe: region `FLASH' overflowed by 2976 bytes

The b0n bootloader links fine with this output:

Memory region         Used Size  Region Size  %age Used
           FLASH:       23874 B      34176 B     69.86%
             RAM:        3528 B        64 KB      5.38%

As you can see there is 10KiB unused space in the b0n partition. Therefore I tried to reduce the size of this partition from 0x7800 to 0x6800. I tried to set the config variables CONFIG_PM_PARTITION_SIZE_B0_IMAGE in the corresponding sysbuild conf files (sysbuild/b0n/proj_fota.conf and sysbuild/ipc_radio/proj_fota.conf) or in sysbuild_fota.conf (with SB_ prefix), but my setting is ignored or there is a cmake configure error.

How can I reduce the b0n partition size?

[Amanda Hsieh]

Hi, 

Could you build for the release version: -DFILE_SUFFIX=release?

How do you build the nrf_audio sample as BIS headset with enabled FOTA? Using command or VS code? Could you provide the command or build configuration of VS code? Please provide more clear information to help reproduce the issue. 

Regards,
Amanda H.

[Benno Trutmann]

Hi Amanda.

I used the west command:

$ west build -d build/test -p -b nrf5340_audio_dk/nrf5340/cpuapp --sysbuild -- -DFILE_SUFFIX=fota -DEXTRA_CONF_FILE=broadcast_sink.conf

whereas broadcast_sink.conf contains the following:

CONFIG_TRANSPORT_BIS=y
CONFIG_AUDIO_DEV=1

Here is the build log:

4807.build.zip

[Benno Trutmann]

I tried to build a FOTA variant now with a nrf5340_audio/sysbuild/ipc_radio/prj_fota.conf copied from prj_release.conf with the following disabled:

CONFIG_DEBUG=n
CONFIG_ASSERT=n
CONFIG_STACK_USAGE=n
CONFIG_THREAD_MONITOR=n
CONFIG_SERIAL=n
CONFIG_CONSOLE=n
CONFIG_PRINTK=n
CONFIG_UART_CONSOLE=n
CONFIG_BOOT_BANNER=n
CONFIG_NCS_BOOT_BANNER=n


With that config I managed to link the ipc_radio image, but only in a tiny margin:
Memory region         Used Size  Region Size  %age Used
           FLASH:      226592 B       222 KB     99.68%
             RAM:       55652 B        64 KB     84.92%

Is there more I can disable? I fear for the future, when the softdevice controller grows only a little in size then there is no space anymore.

[Benno Trutmann]

When the build comes to the signing steps I get the following error:

FAILED: signed_by_mcuboot_and_b0_ipc_radio.bin C:/nrf5340_audio/build/sink-fota/signed_by_mcuboot_and_b0_ipc_radio.bin

...

Usage: imgtool.py sign [OPTIONS] INFILE OUTFILE
Try 'imgtool.py sign -h' for help.
Error: Image size (0x37920) + trailer (0x630) exceeds requested size 0x37800

How can I solve this problem?

[Benno Trutmann]

Here is the full build log:

build3.zip

[Amanda Hsieh]

Benno Trutmann said:

How can I solve this problem?

Try to reduce the size of the application by disabling some features in the https://github.com/nrfconnect/sdk-nrf/blob/v2.7.0/applications/nrf5340_audio/sysbuild/ipc_radio/prj_release.conf.  

Do you need b0n to update mcuboot? If not, you can disable it by SB_CONFIG_SECURE_BOOT_NETCORE in the sysbuild_fota.conf. 

[Benno Trutmann]

Sorry for the late reply, I was away.

In sysbuild/ipc_radio/prj_release.conf I found the following enabled options:

CONFIG_BT_ISO_PERIPHERAL=y
CONFIG_BT_ISO_CENTRAL=y
CONFIG_BT_ISO_BROADCASTER=y
CONFIG_BT_ISO_SYNC_RECEIVER=y

I only need a controller which supports the LE audio broadcast source role. Can I disable all these options except CONFIG_BT_ISO_BROADCASTER? I found no documentation about these options.

Regarding setting SB_CONFIG_SECURE_BOOT_NETCORE=n: Is then updating the ipc_radio image still possible but updating the b0n image is not possible anymore?

[Amanda Hsieh]

Hi,

Benno Trutmann said:

I only need a controller which supports the LE audio broadcast source role. Can I disable all these options except CONFIG_BT_ISO_BROADCASTER? I found no documentation about these options.

Yes, you also can build as Broadcast source. See https://github.com/nrfconnect/sdk-nrf/blob/v2.7.0/applications/nrf5340_audio/broadcast_source/Kconfig.defaults#L18 

Benno Trutmann said:

Regarding setting SB_CONFIG_SECURE_BOOT_NETCORE=n: Is then updating the ipc_radio image still possible but updating the b0n image is not possible anymore?

It still can update ipc_radio image for the netcore instead of mcuboot. 

-Amanda H.