https://devzone.nordicsemi.com/f/nordic-q-a/22258/using-dfu-to-update-softdeviceI&#39;m using nRF52 + s132v2.0.0 + SDK11.0.0. I want to be able to update to s132v4.0.2 (or so) + SDK13.0.0 via DFU. I&#39;m planning on modifying the bootloader start address to 0x77000 with size 0x7000 (to allow for a slight modification which required a pageen-USTelligent Community 13Tue, 23 May 2017 13:46:22 GMThttps://devzone.nordicsemi.com/thread/87486?ContentTypeID=1Tue, 23 May 2017 13:46:22 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c225da7a-625a-4d7c-822f-bac3a4fa83fcHung Bui<p>Hi Tosa,</p> <p>The 2 RAM regions in the bootloader RAM setting in SDK v11 is to support the bond forwarding feature of that bootloader. So that we can reserve the RAM area to store bond information and can forward the bond information from application to the bootloader. The bootloader then can use that bond information in IRAM2 to reload the bond information (the LTK key for bonding).</p> <p>On Secure DFU from SDK v12, that feature is removed. Now we simply change the address of the bootloader (+1 in the default address) and let the phone connect to the bootloader as a new device.</p> <p>IRAM1 in SDK v11 is different from IRAM1 in SDK v12 and later because the softdevices are different and the requirement for RAM reserved for the softdevice are different. Also when you change the configuration (such as different number of central/peripheral, bandwidth) the RAM reserving for softdevice also change.</p><div style="clear:both;"></div>