I get asked a lot if it’s safe to flash changes to a DME over OBD2. The answer is yes, it’s perfectly safe providing you take precautions.
Before starting on DME tweaking mission, it’s always best to take a read from your DME so you have a known good working backup. Save this backup somewhere safe and ensure you don’t overwrite it by accident.
In the video below I deliberately flash junk to my DME and leave it in a state where it will not start or run the car. Many people call this state ‘bricked’, it’s where the device is as much use as a house brick! 🙂
Recovering from the bad flash is easy…you just re-flash your known good backup!
Once you’ve recovered your DME using the known good backup, the car will start, run and drive as it did before you bricked it.
Before flashing your DME again, it’s best to try and identify what caused your flash to fail, it could be something as simple as an interrupted flash because you kicked the OBD2 cable from it’s port mid flash, or you flashed a binary from another vehicle by accident.
Recovering from a bad flash after writing a bad full bin to the DME requires a different approach and is much more involved, that’s why a reading and writing partial dumps is the safest way to flash your DME.