This worked the first time both ways on my 2004 Allroad BEL ME7.1.1
All of this while in the car. Read through OBD my stock ECU and then bootmode the spare one that I couldn't match with VCDS although I had all PIN #s...
The bootmode worked the first time around, even on the moody 7.1.1 to my surprise. I was ready for it though with the little tool I made and described below changed to a 5k resistor and removing the cluster fuse (#15 on the C5).
I wanted to give some guidance as to how to get into bootmode while in the car AND not requiring help from someone else:
I bought a few things at RadioShark and I also pictured the receipt so you can get just show up at the store and ask for the same reference #s.
I used some cable from a charger. You need 2 cables, long enough to go from the battery to the inside of the car (4 to 5 feet), the other one long enough to go from the inside back to the ECU location (2 to 3 feet).
On one end of long cable, I stripped for connection to the battery. About of 1/2 inch of visible copper should be good. The other end of the long cable connect (welded for me) to one side of the switch. Top side on picture below:
The other cable will have this perfect croc pliers small enough to pinch PIN 24 without touching the other pins on one end:
on the other end, a 1K resistor (I had to go to 5k to work with the 7.1.1 so I ended up welding the 5 1k resistors in the Radioshark package in series, no picture) and then the resistor to the other side of the switch as seen above on the bottom side. Tested the whole thing, pretty good at 982 ohms on and infinite off. Perfect!
Switch ON
Switch OFF
More pictures of the in situ action:
pin side :
It looks like it could on this picture but the neighbor PINs are not touched by the pliers:
Battery side:
Finally, the switch getting inside the car:
Got into boot mode right away once I had the 5k resistance and defused the cluster. You have to turn the switch on before you turn the ignition and wait for about 3-5 seconds. I did all this on the battery no charger but all accessories off, because the 7.1.1 is so picky and doesn't like voltage above 12.5v...
No more excuses. Might have to relocate this post somewhere else Tony....