BQ40Z50-R2: Changing the UNSEAL and FULL ACCESS keys

Kevin Knicker

Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQSTUDIO

Tool/software:

Dear TI,

I am attempting to change the UNSEAL keys using the Advanced Comm SMB commands via bqStudio.
I followed an example from a previous post to try it out to see if it works, however my results have not been successful.

The steps I followed were from this previous post:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/781400/bq40z50-r1-change-security-keys

I followed those steps except this is what I see when entering the commands:

Note when I Read Block command=23 I get a value that doesn't match as I was attempting to confirm the new key matched.

I then tried to SEAL the pack to test it out and now the changed unseal keys do not work, nor do the default keys.

Is there something I am doing incorrectly?

I have another pack that I can use to try to change the keys from scratch.

Regards,

Kevin

11 months ago

0 Anthony 11 months ago

TI__Mastermind 28470 points

Hi Kevin,

Was the gauge in a fully unsealed state when these changes were made? If the gauge is in sealed then I do not believe reading back will produce the key values. If the gauge was unsealed during the time the keys were changed, did reading 23 back out show the right keys/

Regards,

Anthony

0 Kevin Knicker 11 months ago in reply to Anthony

Expert 1091 points

Hi Anthony,

The gauge was unsealed when performing the key change.
I was able to unseal the pack with the new keys.

I had entered the values incorrectly using the Commands UNSEAL prompt.

I believe it's supposed to be in little endian format which I didn't do the first time.

It's working now even though the Read Block doesn't read back the right keys.

Thanks,

Kevin

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BQ40Z50-R2: Changing the UNSEAL and FULL ACCESS keys