DFU from SDK16.0 to SDK17.2

[hossein_m]

Hi,

I am trying to test the eligibility of updating my project from SDK 16.0 to 17.2 using DFU. I programmed just softdevice and bootloader of SDK 16.0 and made a package containing bootloader, softdevice and application of version 17.2. In nrfutil I set --sd-req to 0xCA and --sd-id to 0xCAFE, but when performing DFU NRFConnect's logger shows the error "SD version failure (code = 7)". I tried again with --sd-req 0xCA,0xCAFE but received the same error.
Can yo give me some advice to fix this? 

[hossein_m]

Solved!
I didn't have the same key in both boot loaders. however, the logger error was really misleading.