This how-to I'm writing to conclude my experience. I have a chipped 06A 906 032 KQ ECU, and the chip was so shitty that I wanted to start from the scratch. I needed an original firmware. But I couldn't find it anywhere, so I decided to flash a compatible one.

DISCLAIMER: I describe my experience based on the 1.8t engine and ME7.5 Bosch ECU. It might or might not be the same for your case.

1. Find a suitable candidate. There is a list of ECUs for 1.8t engines. As you can see, there are a number of possible candidates for every engine model. For example, for my AWV there:

06A 906 032 FD
06A 906 032 DP
06A 906 032 GB
06A 906 032 KQ
06A 906 032 PT
06A 906 032 EM (notes - auto)
06A 906 032 DN (notes - auto)
06A 906 032 GA (notes - auto)
06A 906 032 KR (notes - auto)
06A 906 032 PR (notes - 5spd auto) 06A 906 032 PS (notes - 6spd tiptronic)

You can try to get a firmware for another (but similar) engine model. In my case, I tried a firmware for AWP, and it worked fine. Ensure that the other engine has the same hardware, or you'll have troubles. The minimum list of affected hardware is:

- O2 sensor type
- Fuel injectors
- MAF
- N75 valve
- etc

2. Find an original firmware for a compatible ECU. The more alternatives you find, the better, since some firmwares might be incompatible.

3. Ensure hardware is the same. It's easy for 1.8t, according to what Marty says)
At least, check that the size of a new firmware is the same as the original.

4. Be ready for immo adaptation. When you flash a new firmware, expect that they won't negotiate with immo from scratch, and the engine won't start. You might need to adapt it.

Background: an ECU has two types of memory: read-only memory, where the main executable code is stored (a firmware of 512kb or 1mb or similar) and EEPROM - a small chip (512 bytes) that ECU can use as a persistent storage. When you flash your firmware, you don't touch EEPROM, it can be flashed only in boot mode (or by desoldering the chip).

4.1. Restore an SKC from your EEPROM. For this you need to dump your EEPROM, you can use me7_95040.exe).
Then you can restore an SKC from it using 95040tool.
Also, you can restore an SKC by a Hex editor: more here.

4.2. Find out what type of immo do you have by using the how-to from Ross-Tech.

5. Be ready for boot mode flashing (taking an ECU out of a car and open its case). Even if you have all the necessary information, new firmware might not be able to adapt to the existing immo. I guess it's because a firmware expects a different immo module than a present.

In my case, I tried three different firmwares. In one ECU didn't want to even login, in the other two, ECU allowed to login, but failed to adapt (System Not OK).

Also, it might lock the ability to flash a firmware via OBD (I tried with MPPS, it gave an error every time I tried to reflash)

In this case, you can try the next firmware or disable immo on this on. Unfortunately, if you can't flash via OBD anymore, the only way is to flash a firmware is via boot mode.

To disable immo, you need to change and flash EEPROM. Currently, you can flash EEPROM only in boot mode. Use  95040tool to modify your EEPROM and me7_95040.exe to flash it.

This is a good post about connecting an ECU on a bench.

6. Try and flash. Good luck.

FAQ

Can I use an automatic gearbox firmware for my manual

I haven't tried, but it should work in theory. You'll get a lot of DTC errors regarding auto tranny (that you don't have), and I'm not sure that Recoding via VCDS would help (if you sent manual gearbox instead of auto). You might need end up with clearing those DTC in a firmware (advanced level)

Can I keep my EEPROM unchanged?

It's better to keep. Considering that people flash common EEPROMs instead of modifying own ones, they are compatible in a wide range. So new firmware should work without any problems. EEPROM contains VIN code, ImmoID, SKC, personal adaptations and coding settings, so it's better to keep your EEPROM and make modifications based on it.

Can I use me7_95040.exe with the VCDS cable?

You can try but some cables are reported not working. For this, you need to install the VCP drivers. Make sure you have a cable recognized with 'with VCP' suffix in the Device Manager. If not COM port appears, ensure you have the 'Load VCP' checkbox set on Advanced tab on the cable properties page in the DeviceManager.

Then you need to load VCDS, and in Settings uncheck the 'Boot in intelligent mode' checkbox.

It's known best to work with a simple dumb cable, like the KKL VAG blue cable.

me7_95040.exe doesn't work

me7_95040 might not work because of multiple reasons:

0x01 - there is no COM interface available. Ensure you point the right COM port number and the cable has a COM port.

0x07 - timeout: there is no communication with ECU. Ensure you have the ignition on, and cable is working

If you can't connect to ECU in boot mode, try different baud rates. In my case, it worked only on 57600.

Ensure you use the latest version. Currently, it's me7-eeprom v1.40.

Please, comment this, ask questions, make additions - I'll try to reflect everything within this post. Thanks

Can you tell more about NB to WB conversion? How did you do that? Did you edit a firmware?
I'm pretty confused by this question since all that firmwares has 'NB' in their title, but I think I have a wideband O2, since I have coefficients instead voltages in 031 group