SLUUCH2 March 2021 BQ40Z50-R2
SEALED to UNSEALED instructs the device to extend access to the SBS and data flash space and clears the [SEC1][SEC0] flags. In UNSEALED mode, DF is readable and writeable. All SBS data is readable in UNSEALED mode as well. Note that although SBS data is also writeable, anything written will be overwritten by the gauge as it updates reported SBS data, so the write action is ignored. Unsealing is a two-step command performed by writing the first word of the unseal key to ManufacturerAccess() (MAC), followed by the second word of the unseal key to ManufacturerAccess(). The two words must be sent within 4 s. The unseal key can be read and changed via the MAC SecurityKey() command when in the FULL ACCESS mode. To return to the SEALED mode, either a hardware reset is needed or the MAC Seal Device() command is needed to transit from FULL ACCESS or UNSEALED to SEALED.
The default UNSEAL key is 0x0414 and 0x3672. To go from SEALED to UNSEALED, these two words must be sent to ManufacturerAccess() (MAC), first 0x0414 followed by 0x3672, both sent sequentially with the second word sent within 4 seconds of the first.