https://devzone.nordicsemi.com/f/nordic-q-a/3545/flash-write-after-flash-erase-failsHi I&#39;m using sd_flash_erase to clear a page in flash. The event NRF_EVT_FLASH_OPERATION_SUCCESS comes to my sys_evt_dispatcher. After the event has arrived I continue with sd_flash_write. Now two different things can happen, If the page was alreadyen-USTelligent Community 13Wed, 20 Aug 2014 14:11:08 GMThttps://devzone.nordicsemi.com/thread/12836?ContentTypeID=1Wed, 20 Aug 2014 14:11:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:99943589-8fc5-4680-8f19-bd042a585950H&#229;kan Wennerholm<p>Hi,</p> <p>Thank yo for the answer.</p> <p>The values of my pointers are the same in both cases, sorry I forgot to write that in my initial question. I check the content of the flash with a memory window in the Keil-debugger. When I see only FF:s there the erase works, event triggers, write works and event triggers again. If I see something else but FF:s then the erase works and triggers its event, but the following write fails even though the pointer values are exactly the same as in the previous run.</p> <p>Best regards /Håkan</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/12835?ContentTypeID=1Wed, 20 Aug 2014 13:17:40 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a79af531-e4db-44a1-b818-7282ba9cde2bJohn<p>That error code should only be returned in two cases: 1) Your flash address (p_dst) is out of the flash memory range; 2) Either of your p_src and p_dst pointers are not aligned to a 4 byte boundary. I do not believe that sd_flash_write checks that the page is empty before it writes. Can you verify in the failure case what the values of the pointers are?</p> <p>How do you know the page is empty or not when this failure occurs?</p><div style="clear:both;"></div>