Thank you for posting really good content.
I have a small question about the data sharing between the bootloader and the application.
In general, in this implementation, I know that the linker represents the memory offset and accesses the variable using the attribute((section(.NAME)) keyword in the code. (eg. https://www.reddit.com/r/embedded/comments/f2yqr0/sharing_mcu_memory_region_between_bootloader_and/)
I think your way is to express these memory offsets in your code, is that correct?