https://devzone.nordicsemi.com/f/nordic-q-a/11150/dfm-bootloader-flashHello Everyone, I was taking a look at the PCB in Ditto . It uses an nRF51822 and supports firmware updates from their app which means they put a bootloader on it. I&#39;ve attached pictures of the PCB. I don&#39;t see any headers; just randomly placeden-USTelligent Community 13Wed, 06 Jan 2016 12:25:04 GMThttps://devzone.nordicsemi.com/thread/41790?ContentTypeID=1Wed, 06 Jan 2016 12:25:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b079ae8e-581c-4549-9110-ccdc48638b2aAnders Strand<p>Hello.</p> <p>It is possible that they program the chips via those pads, but as you say it would require a custom setup.</p> <p>It is common to have the distributor or a third party program bootloader/application into chips when producing in large quantities. Contact a local distributor if you want more information about that.</p> <p>-Anders</p><div style="clear:both;"></div>