SLUUCH2 March 2021 BQ40Z50-R2
This is a read/write command for two-word UNSEAL, FULL ACCESS, DF Read Only, Manual PF, Lifetimes Reset and Override keys.
When reading the keys, data can be read from ManufacturerData() or ManufacturerBlockAccess(). The keys are returned in the following format: aaAAbbBBccCCddDDeeEEffFFggGGhhHHiiIIjjJJkkKKllLL, where:
| Value | Description |
|---|---|
| AAaa | First word of the UNSEAL key |
| BBbb | Second word of the UNSEAL key |
| CCcc | First word of the FULL ACCESS key |
| DDdd | Second word of the FULL ACCESS key |
| EEee | First word of the DF Read Only key |
| FFff | Second word of the DF Read Only key |
| GGgg | First word of the Manual PF key |
| HHhh | Second word of the Manual PF key |
| IIii | First word of the Lifetimes Reset key |
| JJjj | Second word of the Lifetimes Reset key |
| KKkk | First word of the Override key |
| LLll | Second word of the Override key |
The default UNSEAL key is 0x0414 and 0x3672. The default FULL ACCESS key is 0xFFFF and 0xFFFF. The default DF Read Only key is 0x7632 and 0x1712. The default Manual PF key is 0x2857 and 0x2A98. The default Lifetimes Reset key is 0x2B14 and 0x2C8A. The default Override key is 0x2D18 and 0x2E9B
It is highly recommended to change the UNSEAL, FULL ACCESS, DF Read Only, Manual PF, Lifetimes Reset and Override keys from default.
The keys can only be changed through the ManufacturerBlockAccess().
Example: Change UNSEAL key to 0x1234, 0x5678, and leave the other security keys at their default values.
Send an SMBus block write with Command = 0x0035.
| Data | = MAC command + UNSEAL key + FULL ACCESS KEY + DF Read Only key + PF key + Lifetimes Reset key + Override key | |||
| = 35 00 34 12 78 56 FF FF FF FF 32 76 12 17 57 28 98 2A 14 2B 8A 2C 18 2C 9B 2E | ||||
The first word of the keys cannot be the same. That means an UNSEAL key with 0xABCD 0x1234 and FULL ACCESS key with 0xABCD 0x5678 are not valid because the first word is the same.
This is because the first word is used as a “detection” for the right command. This also means the first word cannot be the same as any existing MAC command.