Secure bootloader modification for open/secure mode and multiple key supporthttps://devzone.nordicsemi.com/f/nordic-q-a/126195/secure-bootloader-modification-for-open-secure-mode-and-multiple-key-supportHi there, We have a mass produced product with a modified secure bootloader (from SDK17). This BL has BLE and USB and we bolted on an SPI flash transport for OTA updates over 4G/WIFI and some extra logic to make single bank updates more reliable.en-USTelligent Community 13Thu, 18 Dec 2025 13:10:52 GMTRE: Secure bootloader modification for open/secure mode and multiple key supporthttps://devzone.nordicsemi.com/thread/557328?ContentTypeID=1Thu, 18 Dec 2025 13:10:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:276c05be-d53b-4fa9-942d-334929990414Hung Bui<p>Hi Opcode,&nbsp;<br />I think same question has been asked before. You can take a look here&nbsp;<a href="https://devzone.nordicsemi.com/f/nordic-q-a/50296/disabling-bootloader-security-without-customization">Disabling bootloader security without customization</a>&nbsp;</p> <p>Thing hasn&#39;t changed much since then, I think it&#39;s still the only option. You would need to modify the&nbsp;&nbsp;NRF_DFU_REQUIRE_SIGNED_APP_UPDATE to a runtime flag.&nbsp;</p><div style="clear:both;"></div>