https://devzone.nordicsemi.com/f/nordic-q-a/15350/how-to-write-nvm-flashHi, I use the nrf24le1 device in my design. I want to stroe data when power is off, so I write data to the NVM flash. But something is wrong in my design, could you help me ? I have two codes, the first code is described as follows: The flash is earseden-USTelligent Community 13Tue, 26 Jul 2016 12:32:00 GMThttps://devzone.nordicsemi.com/thread/58660?ContentTypeID=1Tue, 26 Jul 2016 12:32:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b5fd4e32-f03f-4024-9288-e4e107659e37Hung Bui<p>@Liu: How did you flash the new program ? There is a chance that the whole chip is erased before you flash the second firmware. This explain why you see 0xFF when you read on the 2nd firmware. If you don&#39;t switch firmware, but simply do this:</p> <ul> <li>Read the address,</li> <li>If it&#39;s 0xFF then write to the address a value, 0x01 for example</li> <li>If it&#39;s 0x01 then do something else.</li> </ul> <p>Then you don&#39;t have to switch firmware to test the flash writing.</p><div style="clear:both;"></div>