burn fuses

[sapirbuz]

Hi,

How can we burn the fuses without an external flash on our board?

Can we use the internal ROM to do it?

sapirbuz_0-1679415733546.png

[JorgeCas]

Hello,

On the i.MX8 and i.MX8x families the OTP memory is part of the security subsystem and is controlled by the SCU and SECO only. Please refer to this blog post about how users can read and write eFuses.

Understanding how to burn eFuses on i.MX8 and i.MX8x families.

Best regards.

[sapirbuz]

Sorry, but i still don't understand if it is possible to burn fuses without an external flash, and how to do it in case it is possible

[JorgeCas]

Hello,

Yes, you can burn fuses internally using U-boot, once the board is flashed you can use U-boot commands to read/write efuses using the SCFW API functions that are specified on the blog that is on the past answer.

Best regards.

[sapirbuz]

What do you mean by "when the board is flashed"?

[JorgeCas]

Hello,

It means that you have an image flashed on the board and it is able to boot.

Best regards.

[sapirbuz]

If I have an image flashed on the board, it means that I have an external flash on the board, right?

But the external flash wasn't enabled (because we need to burn the fuses first) so it is like we don't have an external flash on the board.

How can we burn the fuses without an external flash on our board and we don't have an image flashed on the board?

[JorgeCas]

Hello,

Got it, it that case it is not possible, you need to flash the MPU to burn efuses.

Best regards. 

[sapirbuz]

You are wrong.

It is possible using the LPSPI NOR/EEPROM.

After setting the "Boot Device" to "LPSPI NOR/EEPROM" , we succeed to burn the fuses.