This document is for v0.6 and later of VW_Flash. The unlocking process has been simplified in the latest version.
If you have an earlier release, please see the previous documentation version!
- Supported Hardware: Macchina A0 (instructions for building a clone here: https://github.com/Switchleg1/AMAleg) or Tactrix OpenPort (genuine). Some other J2534 interfaces are known to work, but an extensive compatibility matrix has not been tested.
- FRF files (Flashdaten) - see below.
- VW_Flash_GUI distribution package from "Releases" on GitHub.
- For Tactrix OpenPort, install the latest OpenPort drivers from here: https://www.tactrix.com/index.php?Itemid=61
- For Macchina A0/homemade clone, refer to the documentation from https://github.com/Switchleg1/esp32-isotp-ble-bridge/releases/tag/v0.90
- For other J2534 hardware, ensure that 32-bit J2534 drivers are installed (the release versions of VW_Flash are 32-bit as most J2534 hardware still ships with only 32-bit drivers).
- Open the VW_Flash_GUI application. You should see a command window as well as the application GUI.
- Open the Interface menu and choose Select Interface.
- To use an A0, configure the J2534 interface using the Switchleg configuration tool.
- On a non-Windows OS, direct connection to the A0 over USB-serial is still supported.
- It's time to get in the car. Turn the ignition on without starting the engine. Make sure a key is in range. On 2020 model year cars, you may also need to open the hood.
- Click Get ECU Info.
- You should now see information in the information area. If you don't, verify that your A0 has the correct firmware and/or you've selected the right interface.
- The most important things to check for now are the Boot Loader Identification. If the last 3 letters are
SC8, you have a Simos18.1 ECU. If the last 3 letters areSCG, you have a Simos18.10 ECU. - Next, check your current VW Spare Part Number and VW Application Software Version Number. Note these for later.
- You're done in the car for now. Go back inside. You've confirmed that your hardware interface works, and you have the information you need to continue.
Create a new folder on your PC to store the files you'll be using. Make two folders inside of this one: Unlock and Tune.
First, you need a specific file that VW_Flash will use to unlock your ECU. Please don't get clever and download a different file for this part of the process. Just use the specified, stock, unmodified file from the VW Flashdaten for the Unlock process:
- If your Boot Loader Identification said SC8, you need
FL_8V0906259H__0001.frf. - If your Boot Loader Identification said SCG, you need
FL_5G0906259Q__0005.frf
Put this file in the Unlock folder.
Simos18 ECUs, like most modern ECUs, do not implement support for reading the flash memory from the ECU over the OBD port. So instead, we need to convert update files from VW's servers (called FRF files) into .BIN files we can use to tune the car.
It's essential that you download an FRF file that matches your car's Power Class.
For US market cars, we've prepared an "update matrix" which will install a specific software version (SC800S50) on your car for which we have both definition (XDF) and various patch files.
- US Golf R / S3, if your VW Spare Part Number matches 8V0906259B, 8V0906259E, 8V0906259H, or 8V0906259K:
FL_8V0906259K__0003.frf - US GTI/A3 2.0, if your VW Spare Part Number matches 5G0906259A, 5G0906259D, 5G0906259L:
FL_5G0906259L__0002.frf - US 1.8T (Sportwagen, Golf, A3 1.8), if your VW Spare Part Number matches 8V0906264A, 8V0906264D, 8V0906264F, 8V0906264K, 8V0906264L, 8V0906264M:
FL_8V0906264K__0003.frf - US TT-S, if your VW Spare Part Number matches 8S0906259C:
FL_8S0906259C__0004.frf
If you don't have one of these box codes (for example, you are not in the US), you need to locate an update file which matches your VW Spare Part Number and VW Application Software Version Number. Or, you can locate a newer update file to work off of.
- Open the VW_Flash_GUI.exe.
- Pick File -> Extract FRF...
- Pick the FRF file you put in the Tune folder above.
- Pick the Tune folder.
- Wait a few seconds.
Open up the Tune folder and you should see the following:
The FL_xxx_x.bin file is a "full read" of your ECU, which can be used with file patching and tuning services like VehiCAL. The FD_4.CAL.bin file is the "calibration" segment of your ECU, which can be used with some tuning tools. The other .bin files are other segments of your ECU, for advanced tuning use.
In your Unlock folder, you should have either FL_8V0906259H__0001.frf or FL_5G0906259Q__0005.frf.
In your Tune folder, you should have a FL_XX_XX.bin file matching your car, either directly or via the compatibility matrix above. For example, for my USDM Golf R I have FL_8V0906259K__0003.bin .
- Set aside at 2 hours where you won't need your car. The full unlocking process takes about 30 minutes, but if something goes wrong, you'll want time to troubleshoot and return to stock. After you've done this once, flashing a new tune (Calibration) takes about 20 seconds.
- To be safe, it's recommended that your car be on a battery tender, but not required. Same for your laptop.
- Enter the car. Turn the ignition on, but the engine off. Ensure the key is in range.
- Pick Get Info again to make sure your hardware interface is still working.
- Pick "File > Unlock ECU" and select the FRF file from your unlock folder.
- Click "Unlock ECU."
- Wait a long time. You should see continuous progress updates as the process proceeds.
- When the process is complete, you should see Finalizing... and then DONE messages in the information box.
- Now click Get Ecu Info again. Check the VW Hardware Number. It should have changed to X13. If it did, congratulations. Your ECU is now in a Sample Mode bootloader and ready to take new software.
At this point, your car will not start or run. It is in a patched bootloader, without any software. You now need to install software on it.
- Pick "Open Folder..." and navigate to your Tune folder.
- Pick "Full Flash Unlocked (BIN/FRF)".
- Pick the
FL_XX_XX.binfile matching your car. This example is for a US Golf R which originally had 8V0906259H__0002 on it, so I picked 8V0902659K__0003 as an update. It is critical that you make sure that this BIN either matches your car's software version, or is compatible per the matrix above. Do NOT pick the file you used to unlock the car. - Pick Flash.
- Wait a little less time than you had to last time. When the process is complete, you should see Finalizing... and then DONE messages in the information box.
- Now click Get Ecu Info again. Check the VW Spare Part Number. It should have changed to the box code you selected for flashing.
From here on out, your car will accept unsigned software blocks. You can select Calibration Flash Unlocked to flash only a modified Calibration area, which should take only 20 seconds or so. If you have a modified BIN with ASW changes, for example from a fileservice like VehiCAL, you can flash it using "Full Flash Unlocked" again.
Don't panic. It is almost impossible to brick an ECU using this process. The only way to cause major problems is to flash a file for a car from the wrong country without a matching Power Class, due to a bug in the immobilizer. For most other issues you can imagine, for example, if power is interrupted, the system crashes, or the connection is broken, you can always safely repeat an operation until it works. For example, if your Unlock process is interrupted, simply try again.
The best thing to do if something goes wrong, you've tried repeating the failed operation, and you're desperate, is to have a stock FL_XXXX_XXX.frf file available for your car. Simply select Flash Stock (Re-Lock) and pick your stock FRF. Click Flash, and allow the process to complete. Your car will be re-locked but it will run again.
Feel free to open a GitHub issue, but you MUST include the following 3 files if you want help:
flash.log , flash_details.log, and udsoncan.log . If you don't provide these 3 files (or you take phone pictures of your screen or some other ridiculous thing), I can't help you because I don't have information about what went wrong.