no its in the car. The weird thing is I was able to connect a few hours earlier. I was gonna try removing the fuses today and see if that helps out. I know the car has some sort of tune on it but its a shitty tune.

BFB is A4 , is it B6 or B7 ? B7 cant be read with Nefmoto at all.. I dont know why .

I was showing an acquaintance the ropes of tuning and I guided him to your thread. I told him prior he needed to hook his battery up to a charger and use a multimeter/voltimeter to monitor the voltage during the duration of the flash procedure, Then he told me I was wrong because it doesn't say anything about that in here lol  ... So I skimmed through the guide and I didn't see it either.

I'll admit, maybe we both accidentally missed it, but if in fact theres nothing about it there, maybe it would be worth while to add it?

If it is there then excuse our oversight and carry on lol 

The ECU could care less about the voltage unless it drops significantly below 10V. There is pretty strong voltage rectification going on, caps and so on.
The ECU will flash when the car doesn't even have enough capacity left to crank. Because the usage is miniscule.

The only times you need a battery charger are when:
1. The ECU turns the fans on during flashing.
2. The flash is very long (30+ minutes)
3. The car has a nearly dead battery

In fact I screwed up against point 1 on a Bosch ECU once, and the voltage oscillated so much that the fans stopped and then restarted constantly, but the ECU completed the flash just fine.
A lot of the shit you do at the dealership isn't really relevant when you know what you are doing and how things work.

As to the reason why the flash fails - security access is denied.
Can be due to modified seed/key algo, can be also due to a number of other things - the engine running, previous security access attempts with incorrect seed/key (resulting in lockout) and so on.
On some Renault ECU's even because engine temp is above a certain number. Voltage is not it though - these ECU's usually flash fine on bench at 10 volts.

We are not talking about flashing all the modules in the car here, just the ECU.
Why you don't need to have charger? For the simple reason that:
1) If you are using correct protocol to write, you can't brick the ECU even if the power cuts out - you will always be able to get into the loader again and flash again.
2) It's a hassle to connect it every time, can't be done on the road and so on.

As I've said - I've been doing this for a while and I only recall ONE case through the thousands of times I've flashed ECU's in various cars that I had a write fail due to voltage dropout... and that was recovered swiftly after simply connecting a charger and restarting the write. I wasted maybe 10 minutes max instead of wasting 10 minutes per write on shit that is extremely unlikely to give you any problems.

I am sure that just as there are ECU's that reject security access when the coolant temperature is above a certain value, there are also probably some ECU's that reject security access based on too low voltage. Although I have never experienced this yet.

This all said - I do have a 30 amp charger with some very long leads wallmounted in my dyno room. And I have countless others around the workshop. If I am flashing anything that takes longer than 20 minutes I tend to connect the charger. However, I've been usually doing that AFTER the write has already started (because I have nothing better to do) - never had an issue with that either.

That's because you are not using correct protocol to flash it. Using correct protocol there are bit(s) set that notify the loader whether flashing was completed.
When overwriting the loader usually another loader is written to a different area and a pointer is set to it before the initial loader is erased.

I am sure with a factory tool you can turn of power nearly at any stage of the flash process and it will successfully restart the write.

Quote:
"If you are unsure what size your ECU is, a quick google will probably answer the question (search for the part number that nef lists when you connect, e.g. “KWP1281 connect info: 6A906032HN”, and ecu size), if not the flash size is listed on the top of the chip inside of the ECU. You can read a 400BB flash using the 800BB memory layout. It will read an extra 512kb past the end of the file, if you chop it in half you are good to go."

Great but is there a layout so I know which chip to look at?!?!
The 2 big ones are CPUs apparently, the long one has a white sticker...
I have looked for '512'or '1024' but nothing.