nrf51822 can not used to cellphone to "DFU" download the XXX.zip. The public_key is good and the code in SDK is not changed.

nrf51822 can not used to cellphone to "DFU" download the XXX.zip. The public_key is good and the code in SDK is not changed.https://devzone.nordicsemi.com/f/nordic-q-a/61873/nrf51822-can-not-used-to-cellphone-to-dfu-download-the-xxx-zip-the-public_key-is-good-and-the-code-in-sdk-is-not-changedi am using the flash 256K and ram 32k of NRF51822. the examples of SDK12.1.0 is includes dfu/bootloader_secure and ble_peripheral/ble_app_uart. when i was used in the software of nrfgo studio to download the two examples, I can not used the "DFU" to downloaden-USTelligent Community 13Wed, 27 May 2020 11:19:42 GMTRE: nrf51822 can not used to cellphone to "DFU" download the XXX.zip. The public_key is good and the code in SDK is not changed.https://devzone.nordicsemi.com/thread/251922?ContentTypeID=1Wed, 27 May 2020 11:19:42 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f275fd56-16dc-46eb-8655-c856c29b4762Amanda Hsieh<p>Hi, </p> <p><span>I would recommend taking a look at </span><a href="https://devzone.nordicsemi.com/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader">this tutorial</a><span>.</span></p> <p><span>-Amanda H.</span></p><div style="clear:both;"></div>