BQ78350-R2-DEVICE-FW: UNSEAL/SEAL Problem

Philipp Knabl

Part Number: BQ78350-R2-DEVICE-FW

Hi everyone,

I have a problem regarding unsealing.

I have one batterypack with a bq78350 + bq76940 which is unsealed. I tried reading the seal password from this device but somehow I am lost.

I also have 3 identical batterypacks with the same specifications, which are sealed.

I have the same password for every 78350 but somehow for the other 3 the password does not UNSEAL them.

Is there a way to find the unseal key for the 3 sealed battery packs via "Advanced Comm SMB" or is there a way how I can read the key from the unsealed battery pack?

The "Advanced Comm SMB" tool is somehow complicated to handle, is there any clear instruction on how to use it?

Best,
Philipp

over 1 year ago

0 Philipp Knabl over 1 year ago

Prodigy 70 points

when i try it this way it gives me the block 0x54 00 07 01 00 00 where in my understanding 0x54 gives me the operation status and not 0x35 for the security keys

0 Shirish over 1 year ago in reply to Philipp Knabl

TI__Guru 57697 points

Hello Philipp,

See BQ78350-R1 TRM section 17.2.31 ManufacturerAccess() 0x0035 Security Keys

To read the keys will require a write followed by a read. This only works in full access mode.

0 Philipp Knabl over 1 year ago in reply to Shirish

Prodigy 70 points

Hi Shirish,

I managed to unlock my devices. It is weird that it does not work with the UNSEAL and UNSEAL_FULL_ACCESS command button. I managed to unseal it with "Write Word" in Advanced Comm SMB. So first the first 4 digits from the unseal_key and within 4 seconds the second 4 digits. Then it was unsealed. Furthermore the same with the Full_Access Key.

Do you have any idea why it worked this way but not over the command buttons?

Gonna mark this as solved!

Best,

Philipp

0 Shirish over 1 year ago in reply to Philipp Knabl

TI__Guru 57697 points

Hello Philipp,

Maybe because the button sends the default commands first and there is some kind of security limitation that does not allow immediate retries? But entering the keys itself takes time, so unlikely.

Power management

Power management forum

BQ78350-R2-DEVICE-FW: UNSEAL/SEAL Problem