RE: Uart stubs in NCS v3.4.0

Vidar Berg — Mon, 17 Aug 2026 14:19:15 GMT

Update: the issue should be addressed by this PR: https://github.com/nrfconnect/sdk-nrf/pull/30654 now.

RE: Uart stubs in NCS v3.4.0

Vidar Berg — Wed, 05 Aug 2026 08:59:04 GMT

Hi,

Thanks for the update. I did some preliminary investigation into this. With CONFIG_DEBUG_OPTIMIZATIONS enabled, it seems like you can reproduce the issue with any sample. This issue got introduced by this commit: SPRT: Add custom SPRT: Add custom __assert_func · nrfconnect/sdk-trusted-firmware-m@a4991f0 but the issue is generally masked because assertions are disabled in default release builds.

I suggest you continue using your workaround for now. I have added the issue to our internal bug tracker so it can be addressed in a future release.

Thanks,

Vidar

RE: Uart stubs in NCS v3.4.0

Rote — Mon, 03 Aug 2026 10:13:31 GMT

Hi, sorry for the late response—I was quite busy last week.
I reproduced the error using the psa_tls sample built for nrf54l15dk/nrf54l15/cpuapp/ns with the debug overlay file.

Then I dug into it further and noticed that, contrary to what I initially thought, the error I described did not occur because of the:

CONFIG_TFM_LOG_LEVEL_SILENCE=y


but because of the:

CONFIG_DEBUG_OPTIMIZATIONS=y

Then I got the following output (sorry, I can't paste the logs as a code block, so I'm pasting them as plain text):

/opt/nordic/ncs/toolchains/ccc010f809/opt/zephyr-sdk/gnu/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/14.3.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(tfm_log.o): in function `output_log':
/opt/nordic/ncs/v3.4.0/modules/tee/tf-m/trusted-firmware-m/lib/tfm_log/src/tfm_log.c:18:(.text.output_log+0x10): undefined reference to `stdio_output_string'
/opt/nordic/ncs/toolchains/ccc010f809/opt/zephyr-sdk/gnu/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/14.3.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(tfm_hal_spm_logdev_peripheral.o): in function `tfm_hal_output_spm_log':
/opt/nordic/ncs/v3.4.0/modules/tee/tf-m/trusted-firmware-m/platform/ext/common/tfm_hal_spm_logdev_peripheral.c:14:(.text.tfm_hal_output_spm_log+0xe): undefined reference to `stdio_output_string'
/opt/nordic/ncs/toolchains/ccc010f809/opt/zephyr-sdk/gnu/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/14.3.0/../../../../arm-zephyr-eabi/bin/ld: secure_fw/spm/libtfm_spm.a(tfm_hal_platform_common.o): in function `tfm_hal_platform_common_init':
/opt/nordic/ncs/v3.4.0/modules/tee/tf-m/trusted-firmware-m/platform/ext/target/nordic_nrf/common/core/tfm_hal_platform_common.c:36:(.text.tfm_hal_platform_common_init+0x46): undefined reference to `stdio_init'
/opt/nordic/ncs/toolchains/ccc010f809/opt/zephyr-sdk/gnu/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/14.3.0/../../../../arm-zephyr-eabi/bin/ld: secure_fw/partitions/lib/runtime/libtfm_sprt.a(assert.o): in function `__assert_func':
/opt/nordic/ncs/v3.4.0/modules/tee/tf-m/trusted-firmware-m/secure_fw/partitions/lib/runtime/assert.c:21:(.text.__assert_func+0x2c): undefined reference to `stdio_is_initialized'
Memory region Used Size Region Size %age Used
FLASH: 120252 B 512 KB 22.94%
RAM: 53980 B 128 KB 41.18%
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

RE: Uart stubs in NCS v3.4.0

Vidar Berg — Mon, 27 Jul 2026 13:54:58 GMT

Hello,

I tried reproducing this linker error by building the tfm_hello_world sample with CONFIG_TFM_LOG_LEVEL_SILENCE=y, but was not able to. Are you able to replicate this using the nRF54L15 DK as your build target with one of the SDK samples? I tested with SDK v3.4.0

Best regards,

Vidar