Question about SECURE_BOOT and MCUBoot

[DevinCallahan]

I'm starting to try to figure out a secure OTA process using the 9160 and tools that Nordic has provided in the SDK and I am confused by one thing I'm encountering.

What is the purpose of "nrf/samples/bootloader", which gets included as a child image if "SECURE_BOOT" is selected as an option?  It seems to duplicate a lot of the logic in MCUBoot, but it seems like a fair bit of work has been done so that "nrf/samples/bootloader" can actually chain boot MCUBoot itself.

Can I safely ignore "SECURE_BOOT" and just configure MCUBoot to do my OTA update process and image verification?

Thank you!

[Heidi]

Hi!

When you say you're developing a secure OTA process, are you talking about a modem firmware upgrade, application firmware upgrade, or upgrading of MCUBoot?

The purpose of the immutable bootloader is to verify a second stage bootloader to create a secure bootloader chain. 

I'm sure you've seen this documentation but just in case: Immutable bootloader, Secure bootloader chain.

Best regards,

Heidi