https://devzone.nordicsemi.com/f/nordic-q-a/20198/regarding-dfuHi. I&#39;m using nRF51822AC, SDK12.2.0. S130 v2.0.1. I just want to make DFU program. But I think it&#39;s a little bit confusing. So I want some explain. Q1. What is the difference between bootloader in SDK10 and bootloader_secure? Which document can Ien-USTelligent Community 13Mon, 06 Mar 2017 23:54:08 GMThttps://devzone.nordicsemi.com/thread/78683?ContentTypeID=1Mon, 06 Mar 2017 23:54:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:643b1ebc-24ac-4d6e-a08a-7112bb1d2d64roger.k<p>Thank you so much for your reply. Let me try.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/78682?ContentTypeID=1Mon, 06 Mar 2017 10:32:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:300c0505-33d8-4e06-93c8-7083dfe30577J&#248;rgen Kvalvaag<p>Q1: Bootloader secure is a new implementation of bootloader, with the main new feature being cryptographically signed firmware, ie you store your public key on the target device, and it will only accept firmware signed with your private key.</p> <p>Q2: There are parts of ECC that are still under patent restrictions, so it was probably not advisable for Nordic to ship this component as part of the SDK.</p> <p>Q3: Yes. You can also do softdevice only, bootloader only, and bootloader + softdevice combined, if you have enough free flash memory on your device.</p> <p>Q4: For Android have a look at this: <a href="https://github.com/NordicSemiconductor/Android-DFU-Library">github.com/.../Android-DFU-Library</a> For IOS: <a href="https://github.com/NordicSemiconductor/IOS-Pods-DFU-Library">github.com/.../IOS-Pods-DFU-Library</a></p><div style="clear:both;"></div>