Hardware requirements

• Micro USB cable

• EVK-MIMXRT685 board

• Personal Computer

Board settings

MCUBoot layout

Region	From	To	Size
MCUboot code	0x80000000	0x8003FFFF	256kB
Primary slot	0x80040000	0x8023FFFF	2048kB
Secondary slot	0x80240000	0x8043FFFF	2048kB

• MCUBoot header size is set to 1024 bytes

• Signing algorithm is RSA-2048

• Write alignment is 4 bytes

• MCUBoot is configured to use its DIRECT_XIP image handling strategy

• Flash remapping HW feature is used for zero-overhead image swapping

Image signing example

imgtool sign   --key sign-rsa2048-priv.pem
               --align 4
               --version 1.1
               --slot-size 0x200000
               --header-size 0x400
               --pad-header
               ota_mcuboot_basic.bin
               ota_mcuboot_basic.SIGNED.bin

Note that for the first image flashed manually together with the bootloader additional imgtool options “–pad” and “–confirm” must be used. Otherwise the bootloader would reject the image for missing data in the trailer area.