To flash an OTS map, select the tab Tune > Flash a Custom Map. You will then see a file select screen similar to below. The file select screen defaults to a specific location for Android and iOS. In order to make finding your custom map files easier, you should save them there for easy access.
Android: the file select screen opens at your device’s Download folder. If you are transferring your files from PC via USB, or saving from an email attachment, you should save them there. Most Android OS also have a file browser app for moving files around on your device.
iOS: the file select screen opens at the MHD root folder (you will see the debugging and datalogging sub folders). You can use the “Files” app that comes with iOS to move them to this folder, save them there directly from an email attachment, or if using the PC to transfer, the iTunes PC app.
On this screen, you can also << swipe left on any tune file (*.bin or *.mhd file extensions), and will be presented with some additional file options. From left to right, they are Rename, Share, and Delete.
Each option is detailed below.
Rename: if you select the Pencil icon to rename your file, you will see a popup in which you can change the file name to something easier to remember, or add details about what was changed in the tune.
Share: if you select the Share icon, you will see a popup asking what sharing method to use. For tune files, the only option is Email. If selected, this will open up your device’s preferred email app with the tune file automatically attached.
Delete: if you select the Trash Can icon, you will see a popup confirming if you would like to delete the tune file. Be careful, as this will permanently delete it from your device!
Flash a Custom Tune Process Overview
On the File Select screen detailed above, tap the tune file you would like to flash. This will take you to the next screen, the MHD Flash screen.
Once at the MHD Flash screen, you can either flash the map as-is, or tap Options to adjust the available Flash Options (these are detailed in their respective section below). There are three different flash lengths you will see:
Full Write: this is the longest initial write, which installs MHD for the first time. NOTE: a battery charger is recommended for this! (if not using MHD Black Wifi Adapter)
Long Write: this is triggered when you are adding or removing a flash option that contains custom code / logic we have developed at MHD. It is shorter than a full write but depending on your connection, a battery charger is recommended.
Map Write: this is a very short write, like changing from Stage 1 to Stage 2, etc.
Once your flash options are configured, PLEASE DOUBLE CHECK THE FOLLOWING:
Ignition is in the “Ignition On”, but “Engine Off” state. To achieve this, press the engine start button without pressing the brake / clutch, until the dashboard shows the fuel level.
G-Series and later vehicles must press the “engine start” button 3x quickly to enter into diagnostic mode as displayed on the dashboard. Do not press the brake / clutch to ensure the car does not start.
All cabin accessories, climate controls, and headlights are turned off.
Battery charger is connected if doing a Full or Long write.
Device is in Airplane Mode + WiFi enabled! (if using WiFi adapter)
Ensure CarPlay is turned off completely. (iOS)
Tap the Write button and MHD will begin to flash the vehicle!
During this time, do not open the windows, do not open the doors, do not turn on anything else in the vehicle as it may interrupt the flashing process.
During this time, you may hear a series of chimes as well as the fuel pump running. You may also see a few iDrive error messages. Do not worry, as this is normal.
Once the map is flashed, MHD will put the car into “Normal Operation”, clear codes, and restore coding. After this, it will ask you to turn the ignition off.
Turn off ignition completely, remove key FOB from slot (if applicable), and wait a minimum of 30 seconds before starting the car! The “Service Car” icon may be illuminated for part of this, that is fine.
Congratulations! You have just flashed your first Custom Tune!