Individual Tuner Calibration
- Prepared for one vehicle and its exact hardware
- Can target individual fuel, drivability and performance goals
- Uploaded through the Custom Map area of the app
- Support is provided by the tuner who created the file
MG Flasher MapsBMW
BMW
Custom Flash
Flash an individual calibration prepared for your supported vehicle by an independent tuner. MG Flasher provides the stock-file workflow, upload tools, custom options and supported file processing needed to install the tune through the app.
Prefer a ready-made calibration? Explore OTS Maps →
Custom Flash Overview
From Stock File to Installed Tune.
01
Export the Stock FileShare the original vehicle file from the Custom Flash area.
02
Independent Tuner CalibrationYour tuner prepares a calibration for the vehicle, hardware and fuel.
03
Upload the Custom FileAdd the prepared tune using Upload Mod in the app.
04
Process and FlashMG Flasher performs supported file checks, corrections and the flashing workflow.
Important: MG Flasher is the flashing platform. Calibration quality, suitability and support remain the responsibility of the tuner who created the custom map.
Overview
A Calibration Built Around Your Vehicle.
Custom Flash allows a supported vehicle to be flashed with a calibration prepared by an independent tuner or calibration specialist. Unlike an OTS map, a custom file can be developed around the exact hardware, fuel, performance target and operating requirements of one vehicle.
The MG Flasher app provides access to the original stock file, custom-file upload, compatible Custom Options and the supported flashing process. It does not replace the work of a qualified tuner or confirm that the calibration itself is appropriate for the vehicle.
When Custom Flash Makes Sense
01
Individual HardwareThe vehicle no longer matches a clearly defined OTS configuration.
02
Specific Fuel or Power GoalThe calibration must be tailored to a particular setup or intended use.
03
Custom Code CalibrationA tuner can prepare compatible map data for supported advanced features.
Choose the Right Path
Custom Flash or OTS Map?
Both are installed with MG Flasher, but they are created for different types of vehicle setup.
Defined, Supported Setups
- Prepared for supported engine, stage, fuel and hardware combinations
- Selected and downloaded directly in the MG Flasher app
- Suitable when the vehicle matches the published requirements
- Available stages depend on the connected vehicle
Original Calibration
Start with the Vehicle's Stock File.
After the vehicle is activated in MG Flasher, the original file becomes available from the Custom Flash area. It can be shared from the device and supplied to the tuner as the correct base for that vehicle and ECU software.
The tuner should identify and return the prepared calibration using a clear file name. Do not perform manual checksum calculations before uploading—the supported checksum and RSA processing is handled by MG Flasher during the file workflow.
Example Stock File
Vehicle-Specific Original File
ConnectedCar_3c9a_VIN###.org
btld_3075-000.001.032_swfl_3076-080.017.002_swfk_3c9a...
The exact naming structure varies by vehicle and software. Always use the file generated for the connected vehicle.
App Workflow
From Vehicle File to Custom Tune.
Use a qualified tuner, follow the exact vehicle-preparation requirements and keep the app connected throughout the flash.
Activate the Vehicle
Confirm support, activate the Flashing License and complete any required ECU unlock before using Custom Flash.
Share the Original File
Open Custom Map, download the stock file and send it to the independent tuner preparing the calibration.
Receive the Custom Tune
The tuner modifies the correct base file for the vehicle's hardware, fuel and agreed objectives.
Use Upload Mod
Upload the returned file to the Custom Map page and choose the calibration intended for the vehicle.
Review Custom Options
Select only the supported options appropriate for the tune and installed vehicle hardware.
Process and Flash
Keep the connection and ignition stable until the app confirms a successful flash, then complete the ignition cycle.
File Processing
Checksums and RSA Corrections in the App.
MG Flasher processes supported custom files before flashing, but file processing is not the same as validating the quality of the tune.
Supported File Check
The app reviews the uploaded custom file as part of the supported flashing workflow before the flash begins.
Checksum & RSA Processing
Do not calculate checksums manually. MG Flasher performs the supported checksum and RSA corrections during upload and flashing.
Tuner Validation Still Matters
These technical checks do not prove that boost, timing, fueling or torque targets are safe or correct for the vehicle.
Custom Options
Configure Supported Options Before Flashing.
The available options depend on the vehicle, ECU software, Custom Code version and calibration prepared by the tuner.
Legal and hardware requirements apply.
Some options are intended only for closed-course or off-road use and may require specific hardware. Confirm every selection with the tuner.
Access Requirements
Flashing License and ECU Activation Required.
Custom Flash is enabled by the VIN-locked MG Flasher Flashing License. The DME must also be activated or correctly unlocked before a custom file can be flashed through the OBD workflow.
Unlock requirements depend on the ECU hardware and security level. Use Check Support in the app before purchasing tuning services or preparing a custom calibration.
Supported Vehicle
The engine, ECU and software must be supported by MG Flasher.
Flashing License
The VIN-locked license enables repeated flashing and access to Custom Flash.
ECU Unlock
Complete the in-app, bench or specialist unlock required for the DME.
Independent Tuner
Use a tuner familiar with the platform, vehicle hardware and intended fuel.
Before Flashing
Prepare the Vehicle and Keep the Connection Stable.
A custom file uses the same critical power, ignition and connection requirements as every ECU flash.
Stable Battery Voltage
Use a healthy battery and connect an appropriate charger, especially for activation and longer procedures.
Electrical Loads Off
Turn off lights, HVAC, heated seats, multimedia and unnecessary aftermarket devices.
Reliable ENET Connection
Use the recommended ENET WiFi workflow or a correctly configured cable setup without interruption.
Correct Ignition State
Follow the app guidance for the exact vehicle and do not start, disconnect or leave the app during flashing.
Stock Restoration
Return to the Original Calibration.
The original stock map is created and retained with vehicle activation. It can be selected from the Flashing screen to return the ECU calibration to stock while the vehicle remains activated for MG Flasher.
This normal Stock flash is different from a full uninstall or relock procedure. Use advanced uninstall, coding or backup tools only when specifically instructed by MG Flasher Support.
Open Support Resources →
Return-to-Stock Flow
01
Open the Flashing ScreenConnect the supported vehicle and select the available Stock option.
02
Prepare the VehicleUse the same stable battery, ignition and connection requirements.
03
Flash the Original SoftwareWait for success and complete the required ignition cycle.
FAQ
Custom Flash FAQ.
Common questions about custom maps, stock files, licenses, tuners and flashing.
What is MG Flasher Custom Flash?
Custom Flash allows a supported vehicle to be flashed with an individual calibration prepared by an independent tuner or calibration specialist.
Does MG Flasher create the custom tune?
No. MG Flasher provides the stock-file, upload and flashing workflow. The independent tuner is responsible for creating, validating and supporting the calibration.
Do I need a Flashing License?
Yes. A VIN-locked Flashing License must be activated before Custom Flash can be used for the supported vehicle.
Where do I get the original stock file?
After vehicle activation, the original file is available from the Custom Flash area and can be shared from the device to the tuner.
Should my tuner calculate checksums?
No. The current instructions state that MG Flasher performs supported checksum calculations and RSA corrections during the file upload and flashing workflow.
Can Custom Flash use Custom Code features?
Compatible Custom Code functions can be prepared in an individual tune by a tuner using the correct map pack, codewords and valid calibration data for the ECU software.
Can I store and switch between multiple custom maps?
The app can hold uploaded custom files for the vehicle. Each file must be clearly identified and flashed using the correct Custom Options and vehicle preparation.
Can I return the car to stock?
Yes. The original stock calibration remains available through the Stock option in the Flashing screen for supported vehicles.
Ready for an Individual Calibration?
Use Custom Flash with a Qualified Tuner.
Confirm vehicle support, activate the required license and prepare the complete hardware and fuel setup before flashing.