BELK-TN-011: Lock OTP Areas

Info Box Applies to Bora Applies to BORA Xpress

This technical note was validated against specific versions of hardware and software. What is described here may not work with other versions.

History

Version	Date	Notes
1.0.0	Sep 2020	First release

Introduction

As decribed on ConfigID management page, these informations are stored inside a general purpouse OTP area of the SoC.

This page describes a fix to be done on BORA systems that runs BSP versions older than BELK/BXELK-4.1.2

ConfigID programming

All the SoM are shipped with ConfgID and UniqueID already programmed and locked. The OTP lock ensure that nobody can change this data (unattempted code execution, etc).

It is possibile to execute these operations only using the devel versions of u-boot with the following commands:

configid som_configid <16 byte code>
configid som_uniqueid <32 byte code>
configid som_lock 0

Older BSP issue

In older BSP, due to a u-boot limitation, this OTP area is not really locked and therefore it should be possible to overwrite its value, with possible identification errors during updates.

Starting from the BELK/BXELK-4.1.2 release this issue have been solved.

Fix lock of OTP areas

It is suggested to update the systems that runs older BSP releases to the BELK 4.1.2 and perform the following fixing steps:

• program on boot from the uSD using the u-boot devel version - that can be found on our mirror server - allowing the OTP lock command to be executed
• execute the command configid som_lock 0
• program any u-boot release version to restore the normal operations (this is not required if previous operations have been executed using an external boot from SD)