Hi,

I'm new to this stuff so please don't be rude to me

I have a macbook air with a "dead" battery because I didn't use it for a long time. I tried charging it but it doesn't work, so now I want to revive it. I've read about this problem and I have to unseal it to reset the BQ20z451 chip. I have two problems for this, first I don't know the unseal key (the default key doesn't work) and second I don't have the EV-2300 programmer, but I have a STM32F407 board with which I can communicate with the chip.
My idea is to clone the ev-2300 with the STM32 and use some software to unseal it or buy a new bq20z451 to write the configuration to it with the TI software (I need the EV-2300 for this). I have all the communication from PC (I used a custom HID with the EV2300 PID/VID) to bq20z451, but I have no idea about the other part (bq20z451 to PC). I tried using the same parse, but it doesn't work.

I need help trying to decode the communication IC to PC. Can anyone trace the USB traffic from the EV2300 to try to decode it? Or if you know the parse and want to share it.

thanks

Did you check the health of the battery ?

When a cell enters ultra-low voltage "non-critical state", the controller disables battery output and waits for a connected charger then it start trickle-charging the cells until all cells went safely above ULV state, then the controller removes the flags and self-reset to enable the battery output.. this will take a long time leave the battery on the charger for 24h and if it's in ULV state it will come back automatically..

BUT if the cells are under ULV (out of spec) then they are in a critical/dangerous state that the controller completely disables charging & discharging and blow the fuse "in some batteries" and flag it completely dead, reviving such cells is very unsafe !

also forget about unlocking the chip in original batteries, there is a password "from the manufacturer" to unseal the chip and reset it..

You'll need to replace BQ20Z451 controller with a new "or used with no password" one and program/configure it with full cell details.. this procedure should be done on replaced new cells and not on a revived/already out of spec one..

along with EV2300 programmer you also need a specific version of bqEVSW that made specifically for the 20z451 chip which Ti wont give if you don't own the EV2300 in first place...

a lot of complicated/not recommended & unsafe stuff that you can dodge by buying a new battery

Apple uses standard unseal key, it is available in bq20z45 datasheet.
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First you need to check firmware version of bq20z451 chip.
Apple changed unseal method on batteries which have firmware version v5.11, v7.xx, v9.xx, v10.xx and so on.

But if chip has v2.xx, v3.xx you could be lucky. It could be unsealed standard way.