Originally Posted by outie
If you don't know what you are doing you really shouldn't be updating the firmware yourself. Getting ista to work alone is already challenging. It's not as simple as download a software and click run. It's very risky and you could potentially brick it.
I have to agree with outie on this one. I would start with learning/playing with coding your own car first then move to programming after some time.
You should *never* update the programming on your car without a stable power supply connected to your car. Never attempt to update the firmware on the car's battery power alone, you will seriously harm your ECU's. I have a $400 power supply that supplies a stable 13.8 volts to the car at all times (selectable from 13v to 14.8v) and a cloned OPS head for programming things like the iDrive over the fibre optic MOST port in the car and even then I get a little nervous every time I hit the "update" button.
Being that you are in France, you probably have alot of independent shops around that carry Autologic units, I would get one of them to handle the software update on your car, it would probably be cheaper than buying most of the equipment you need to properly flash the car. Unless, of course, you are a hard core DIYer and spending a couple hundred dollars on equipment isn't a problem.