Hardware requirements

  • MIMXRT700 board

  • Mini/micro USB cable

  • Personal Computer

Board settings

Make sure the board is setup to boot from flash.

MCUBoot layout

In all cases, the MCUBOOT bootloader reserves 256kB at the beginning of the external flash followed by 2MB slots for application.

Region

From

To

Size

MCUboot code

0x28000000

0x2803FFFF

256kB

Primary slot

0x28040000

0x2823FFFF

2048kB

Secondary slot

0x28240000

0x2843FFFF

2048kB

  • MCUBoot header size is set to 1024 bytes

  • Signing algorithm is ECDSA-P256

  • Write alignment is 4 bytes

  • MCUBoot is configured to use its DIRECT_XIP image handling strategy together with FlexSPI flash remapping

Image signing example

imgtool sign   --key sign-ecdsa-p256-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.