https://devzone.nordicsemi.com/f/nordic-q-a/79258/how-to-get-gap-addr-by-nrfjprogExcuse me: What is the register or Flash address that stores the device default MAC? I want to modify the default MAC by nrfjprog.thank you!en-USTelligent Community 13Fri, 03 Sep 2021 15:14:27 GMThttps://devzone.nordicsemi.com/thread/328010?ContentTypeID=1Fri, 03 Sep 2021 15:14:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a12a25b0-4ad1-4393-a0f6-2d15389182beSigurd<p>Hi,</p> <p>The default Bluetooth MAC address is derived from FICR, this is read-only. See this post:&nbsp;<a href="https://devzone.nordicsemi.com/f/nordic-q-a/2112/how-to-get-6-byte-mac-address-at-nrf51822/9000#9000">https://devzone.nordicsemi.com/f/nordic-q-a/2112/how-to-get-6-byte-mac-address-at-nrf51822/9000#9000</a></p> <p>To change the address you need to use the SoftDevice function <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s140.api.v7.2.0/group___b_l_e___g_a_p___f_u_n_c_t_i_o_n_s.html?cp=4_7_4_2_2_1_3_1#gaef69dc212534adf4b78d211edce2267b">sd_ble_gap_addr_set</a>. If you want to set the address with nrfjprog, then your application would need to use this API, and the application would need to then fetch the address you want to set from e.g. the UICR Customer registers,&nbsp;<a href="https://infocenter.nordicsemi.com/topic/ps_nrf52833/uicr.html#register.CUSTOMER-0-31">https://infocenter.nordicsemi.com/topic/ps_nrf52833/uicr.html#register.CUSTOMER-0-31</a>&nbsp;, that you then&nbsp;have written to using nrfjprog&nbsp;memwr command.</p><div style="clear:both;"></div>