https://devzone.nordicsemi.com/f/nordic-q-a/122631/ble-fails-on-connectHi, It feels like i have a follow up question of my ticket here . We are currently developing a product using the nrf54l15 using the nrf connect SDK v2.9.1 with the toolchain of the same version. We want to include BLE with periodic advertisingen-USTelligent Community 13Tue, 01 Jul 2025 08:42:26 GMThttps://devzone.nordicsemi.com/thread/540989?ContentTypeID=1Tue, 01 Jul 2025 08:42:26 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fa96b41f-9db4-43a3-b650-81a2dfa9ad13Kazi Afroza Sultana<p>Hello,</p> <p>Have you tried to run the sample on Nordic DK? If it works on the nRF54L15 DK, then it could be hardware issue on your custom board.</p> <p>MPSL assert error usually relates to HFXO; even though you found the crystal working ok, there may be unproperly soldered decouple capacitors (specially on pin DEC4) on the board or the load capacitor is not correct.&nbsp;</p> <p>There are known issues with the default HFXO latency settings on nRF54L15 series devices, which can prevent Bluetooth events running proerly.&nbsp;<span>The workaround is to increase the configured HFXO startup time or the&nbsp;</span><code dir="ltr">CONFIG_MPSL_HFCLK_LATENCY</code><span>&nbsp;Kconfig option. Specifically, it is recommended to set the HFXO startup time to 1650 microseconds or increase&nbsp;</span><code dir="ltr">CONFIG_MPSL_HFCLK_LATENCY</code><span>&nbsp;by 512 microseconds to allow tuning to complete. This is especially important for nRF54L15, nRF54L10, and nRF54L05 devices&nbsp;</span><a href="https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html#multiprotocol_service_layer_mpsl" rel="noopener noreferrer" target="_blank">Multiprotocol Service Layer (MPSL) Known Issues</a><span>.</span></p><div style="clear:both;"></div>