Unseal the Fuel gauge protection of BQ27541/BQ27542 via i2ctransfer on Linux

bq2754x_unseal.sh

#!/bin/bash
# Simple Script to Fully Unseal the BQ27541 or BQ27542
# Coded by TinLethax 2021/06/02 +7

# structure [Control_command0x00][lower byte][higher byte]
# Unseal first by writing 0x0414 (Sending Big endian )
i2ctransfer -y -f -a 0 w3@0x55 0x00 0x14 0x04
# Then writing 0x3672 (again, Big endian first)
i2ctransfer -y -f -a 0 w3@0x55 0x00 0x72 0x36
sleep 1
#We successfully unseal but we haven't clear FAS bit yet (Full access Sealed)
#We need to TOTALLY UNSEAL the chip by
i2ctransfer -y -f -a 0 w3@0x55 0x00 0xFF 0xFF
i2ctransfer -y -f -a 0 w3@0x55 0x00 0xFF 0xFF
sleep 1
#ensure that our higher byte of control status indicate that Seal and FAS is disabled
#By sending control status subcommand
i2ctransfer -y -f 0 w3@0x55 0x00 0x00 0x00
i2ctransfer -y -f 0 w1@0x55 0x00 r2
echo "on higher byte (second printed byte) must have bit 6 and 5 set at 0"
echo "mine i2ctransfer output read as 0xXX and 0x00 which is fully unsealed"