Is I.MX rt serial boot suitable for board maintenance across the borad's entire lifecycle?

[nicolaponzevero]

Hi all,

we designed an application board based on I.MX rt 1175 and we are now defining the processes we'll use to handle it in its entire life cycle.

We initially planned to keep the serial download selectable by using "GPIO overrides" to force the serial download as described in the processor family reference manual IMXRT1170RM section "10.3.5 Internal Boot mode (BOOT_MODE[1:0] = 10b)"  until we jumped in the note a the end of the chapter.

This note says "The use of the GPIO overrides is intended for development since these pads are used for other purposes in the deployed products. NXP recommends controlling the boot configuration by the eFuses in the deployed products and reserving the use of the GPIO
mode for the development and testing purposes only. "

Can you share the rationale of this recommendation (especially about the second phrase - quoted in bold) to let us understand if it applies to our use case? We plan to use the secure boot, does the availability of the serial download introduce some security concern?

Thanks and regards

nipo 

[_Leo_]

Hi,

Thank you so much for your interest in our products and for using our community.

The boot ROM uses the state of the BOOT_MODE and eFuses or GPIO pin inputs to determine the boot device.

In general, for evaluation or development, it is recommended that the GPIO pin inputs be used so that you can find the most appropriate configuration for your application.

If you are already sure of your setup, for deployment we recommend boot from eFuses. This way you can use the GPIO pin inputs for other functionality.

A secure boot using the HAB is possible in all the three boot modes.

Hope it helps you.

Have a nice day!