Known issues

Known issues listed on this page are valid for the current state of development. For the list of potential issues found regarding Axon NPU, see the Axon NPU changelog page. A known issue can list one or both of the following entries:

  • Affected platforms:

    If a known issue does not have any specific platforms listed, it is valid for all hardware platforms.

  • Workaround:

    Some known issues have a workaround. Sometimes, they are discovered later and added over time.

List of known issues for v2.2.0 release

NCSDK-40250: Bootloader Serial Recovery mode is disabled in release configurations on Thingy:53

In the Gesture Recognition application, bootloader Serial Recovery mode is disabled in release configurations.

Workaround: Enable the following Kconfig options in the MCUboot configuration file configuration/thingy53_nrf5340_cpuapp/images/mcuboot/prj_release.conf:

CONFIG_MCUBOOT_SERIAL=y
CONFIG_GPIO=y

This restores Serial Recovery mode at the cost of increased current consumption.

Affected platforms: Thingy:53

List of known issues for v2.1.0 release

NCSDK-39297: CMake duplicates the board configuration directory in CONF_FILE paths when used with the nRF Connect for VS Code GUI

The application’s CMake setup sets APPLICATION_CONFIG_DIR to configuration/<board>_<qualifiers>/, which causes Zephyr to resolve CONF_FILE relative to that directory instead of the application root. As a result, CONF_FILE must be set to a file name only (for example, prj_release.conf), and must not include the configuration/<board>_<qualifiers>/ prefix.

However, the Kconfig fragment picker in the nRF Connect for VS Code extension inserts the path relative to the application root, for example:

configuration/nrf54l15tag_nrf54l15_cpuapp/prj_release.conf

CMake then prepends APPLICATION_CONFIG_DIR again, the board configuration sub-path is duplicated, and the build fails with an error similar to:

CMake Error at .../zephyr/cmake/modules/kconfig.cmake:318 (message):
  File not found:
  .../applications/gesture_recognition/configuration/nrf54l15tag_nrf54l15_cpuapp/configuration/nrf54l15tag_nrf54l15_cpuapp/prj.conf

Workaround: Set CONF_FILE to the file name only, relative to APPLICATION_CONFIG_DIR, and omit the configuration/<board>_<qualifiers>/ prefix. On the command line, pass the file name directly, for example:

west build -b nrf54l15tag/nrf54l15/cpuapp -- -DCONF_FILE=prj_release.conf

List of known issues for v2.0.0 release

DRGN-27788: Bluetooth LE disables RRAM low-latency mode when using AXON NPU and Bluetooth LE simultaneously on the nRF54LM20B SoC

When running AXON and Bluetooth LE together on nRF54LM20B, Bluetooth LE might disable RRAM low-latency mode during radio activity, which may slow or corrupt an ongoing inference. MPSL sets STANDBY mode in NRF_RRAMC->POWER.LOWPOWERCONFIG at the start of each radio slot and restores the application init value at the end. In a power-optimized application, if the radio slot ends while an inference is running on Axon, the low-power (NRF_RRAMC_LP_POWER_OFF) value will be forced by MPSL, slowing down the rest of the inference.

Workaround: Use CONFIG_MPSL_FORCE_RRAM_ON_ALL_THE_TIME to keep RRAM permanently in STANDBY mode. This setting increases power consumption but ensures reliable performance.

Affected platforms: nRF54LM20B SoC