You forget about MED17 to read it by OBD.
Even original devices can not read all of the MED17 after OBD.
The safest way is to program these drivers in boot mode.
If something goes wrong with MED17 during OBD programming, IMMO flies into the air.
MED17 is programmed on the table without any problem.
1. There is no need to read anything ever - you can use virtual read. You can never damage anything via OBD that is not contained in the frf (uds) / sgo (TP2.0/KWP) container, because this container contains all OBD flashable data.
2. Boot mode reprogramming of VAG MED17 is like 2010 year stuff. I don't see why you would ever do that when you have access to correct tools.
3. Absolutely nothing happens with immo. Immo needs to be only authenticated for starting programming, and it does not need to be re-authenticated until programming is complete. If any programmable section checksum is invalid, the ECU will go into bootloader each and every time. So absolutely NOTHING happens if you program MED17 with a valid file and pull the plug in the process, you can always restart the write.
The only thing that can ever happen is if you program a file with code modification or badly changed map axes where the checksum is correct, but the changes aren't.
But I guess, china tool copyshops still go like "ZOMG YOU MUST DO IT IN BOOT ONLY !!!111".
As for decent tools, there are no clones that will do everything correctly, especially you are going to have a problem getting original files.
Some original tools that work:
* CMDFlash
* Original Kess
* Original New Genius
* X17
X17 and CMD have the best VAG coverage, because they do most gearboxes too, but X17 programming is super slow because their hardware is very bad. CMD is fast.
Some tools that are cheaper and allow to write vag MEDC17 OBD:
* Ecuflasher with VAG module, though I am not sure exactly how getting original files works with that
* Original MPPS.
