https://devzone.nordicsemi.com/f/nordic-q-a/35005/custom-mac-addresses-and-the-bootloaderOn our products, we assign a custom sequential mac address to each unit (we use this number in other places in our system). I believe this is an issue due to the bootloader, which increments the mac address by 1, therefore causing 2 devices in the sameen-USTelligent Community 13Mon, 04 Jun 2018 11:19:31 GMThttps://devzone.nordicsemi.com/thread/134523?ContentTypeID=1Mon, 04 Jun 2018 11:19:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bbc4b1ac-e414-4978-b875-93e7ee56994etesc<p>Hi,</p> <p>For &quot;standard&quot; DFU and buttonless DFU without bonding the bootloader bumps the address by 1 for running in DFU mode (mainly for avoiding trouble with cached GATT table.)</p> <p>In order to stay compliant with our apps you can either use only every other address (e.g. odd numbers only) or you can use buttonless DFU with bonding. For the latter option, you must use buttonless DFU and configure both the bootloader and the buttonless DFU service for the application to use/require bonds. With bonded buttonless DFU the same address is used both in application and in bootloader (otherwise the bond would not work) and also the service changed characteristic is required.</p> <p>Regards,<br />Terje</p><div style="clear:both;"></div>