Latest status of Buttonless secure DFU in SDK 13.0

[sam wagner]

Hi,

I just got the email about SDK13.0 official release. The list of changes in this release include "Secure DFU improvements". What does it mean? Is Buttonless Secure DFU completely supported in this release?

Regards, Sam

[Hung Bui]

Hi Sam,

Compare to SDK v13 alpha, the buttonless example in the SDK v13 official doesn't change much.

• It is still in experimental mode

• Some issues on SDK v12 and 13 alpha were fixed such as the characteristic's write property missing, the bootloader_setting section missing were fixed.

• Now we use RAM retention register GPREGRET to set the flag to enter bootloader mode instead of writing to flash.

• Change the service's UUID to the Secure-DFU UUID

• Change from the DFU control point property from notification to indication

• Requires nRFutil v2.2.0

[Hung Bui]

We don't support bond forwarding yet. But is it a firm requirement that the link has to be re-encrypted when you do DFU ?

If it's OK to do DFU with an open link ( still secure DFU, just no bond) you can think of changing the address of the device when it switches to bootloader.

This also require you to modify the DFU app on the phone to look for the new address after it write the command to tell the application to switch to the bootloader.

If encryption is the requirement, you may have to think of writing some code to forward bond information and re-use it after you switch to bootloader. You can refer to what we have in the bootloader in SDK v11 to know how to do it.