Porting docs are not linked from main doc index page

[willdean]

There is an excellent (well it looks excellent, I haven't actually tried the port yet...) porting doc porting.md, which search engines find if you search for mcuboot porting.

However, this doc isn't actually linked from index.md, which feels like an oversight.

Would the project take a PR to add this into the "MCUboot How-tos" section of index.md?

[nordicjm]

It is actually linked, in a very obscure place on https://docs.mcuboot.com/design.html in MCUBOOT_BUILTIN_KEY: With this option the whole public key(s) used for signature verification must be provisioned to the target device and the used cryptographic library but yes, would be better to have a direct link to it in the documentation (PR welcome)