Originally Posted by ******84
I think that is quite dangerous to do it without additional power supply. If voltage will drop down the flashing process will be stopped. It's not worth to take this risk. Every ECU in your car should be flashed using battery charger or second car as a power donor.
I would agree to disagree but i have flashed over 40 Alpina flashes without battery charger and it went fine...But for added insurance it cant hurt. Other modules like DME, CIC as such I totally agree