https://devzone.nordicsemi.com/f/nordic-q-a/33631/nrf51822xxaa-secure-dfu-bootloader-problemFirst, we implemented ble secure dfu application on nrf51dk. After, we want to program nrf51822xxaa device with same ble secure dfu app. In addition, we saw about rom/ram address (IROM1 start=3AC00 size=5000, IRAM1 start=200025E0, size= 1A20) for thisen-USTelligent Community 13Thu, 26 Apr 2018 09:27:24 GMThttps://devzone.nordicsemi.com/thread/129905?ContentTypeID=1Thu, 26 Apr 2018 09:27:24 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ed5ff687-b9fc-4aa4-9dcd-6e6158893b57Sigurd<p>Hi,</p> [quote userid="71138" url="~/f/nordic-q-a/33631/nrf51822xxaa-secure-dfu-bootloader-problem"]and changed these values from Keil Options for Target tool and build this app successfully with these new ROM/RAM addresses at the end.[/quote] <p>Is the&nbsp;<span>rom/ram addresses you mentioned the new or the old ones?</span></p> <p><span></span></p><div style="clear:both;"></div>