topic Re: LS1046A fuse programming. in Layerscape

LS1046A fuse programming.

Ingo-Roda — Wed, 08 May 2024 06:55:19 GMT

Hi there,

I have a rather simple question, but do not find a clear answer in any of the manuals.

So, how often can a fuse be blown?

As far as I understand, only once, permanently.

The document "LS1046A Datasheet Rev. 4.pdf" says in Table 6:

"5. Only six secure boot fuse programming events are permitted per lifetime of a device."

What does this mean in detail?

Thanks in advance,

Ingo

Re: LS1046A fuse programming.

Oswalag — Wed, 08 May 2024 16:26:00 GMT

Hello,

The reason for the "six" fuse programming are: 1 for testing (burn OTPMK/SRKH, etc), 2 for production (burn ITS and/or WP). 3 to 6 is for revoke keys form key list.
The more you program the fuse, there are more possibilities that you accidentally burn other fuse bit that cause corruption. Base on the above reason, you should not need to burn the fuse more than 6 times.

Have a nice day.

Re: LS1046A fuse programming.

Ingo-Roda — Mon, 13 May 2024 10:56:39 GMT

Thanks, Oswalag.

Just to be 100% certain: a fuse can only be blown once, right!?!

Have a nice day, too,

Ingo

Re: LS1046A fuse programming.

Oswalag — Wed, 15 May 2024 19:56:45 GMT

It is correct.

BR.