BQ24160: Vbatreg increase issue using I2C

Hello,

I'm Using BQ24160 and use Arduino as the Host controller. 

I read all register data using Arduino and those are OK.

Btw, I have tried to increase Vbatreg (up to 4.2V) registry using Arduino. But it's not worked properly. 

I just write 0x8C value to 0x03 register. but it remains the default value.

How can solve this issue ??

Thanks !