https://devzone.nordicsemi.com/f/nordic-q-a/7757/restricted-functionalities-in-isr-contextHi, I&#39;ve noticed that the following s110 API work in my application, when called from the main context, but fail when called from an ISR context (button press interrupt or system event) : pstorage_clear() pstorage_store() bootloader_app_starten-USTelligent Community 13Mon, 22 Jun 2015 16:46:49 GMThttps://devzone.nordicsemi.com/thread/27619?ContentTypeID=1Mon, 22 Jun 2015 16:46:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:51004f3a-4e80-41eb-b36e-fcdaf1e4ee8eJean-Louis Bonnaff&#233;<p>well, for pstorage functions, the flash event callback is never called, and for bootloader_app_start, the application doesn&#39;t restart. Get back to you later for the priorities.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/27618?ContentTypeID=1Mon, 22 Jun 2015 10:40:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e7d39d4e-0a31-4d70-9e86-866e61cc4cedRK<p>what does &#39;fail&#39; mean? They give error codes, they don&#39;t run, the code goes into the error handler or hardfault handler?</p> <p>What&#39;s the interrupt priority of the ISR you&#39;re using? If it&#39;s higher priority than the SVC handler (which is level 2) then you&#39;ll hardfault because you can&#39;t call a SVC call from a higher priority handler. If you&#39;re using APP_HIGH, that&#39;s too high.</p><div style="clear:both;"></div>