BMW M340i
Vehicle-specific tuning page for selected G20 sedan and G21 Touring configurations.
BMW M340i G20 / G21 · B58 ECU Tuning
BMW M340i G20/G21 Tuning
Tune a supported BMW M340i G20 sedan or G21 Touring with the MG Flasher app. Check B58 ECU compatibility, unlock requirements, Stage 1 and Stage 2 OTS maps, supported vehicle features, connection hardware and license options before flashing.
VehicleBMW M340i
ChassisG20 / G21
EngineB58
AppiOS · Android · Windows
BMW M340i Compatibility
G20, G21 and B58 ECU Support
MG Flasher supports selected BMW M340i configurations. Exact availability must be confirmed from the connected vehicle because ECU software and security can vary between production years, markets and software-update histories.
B58 Turbo Inline-Six
MG Flasher tuning availability depends on the exact B58 ECU and supported software release.
Unlock May Be Required
The app identifies whether the connected DME is ready for OBD flashing or requires an external unlock service.
ENET + Latest App
Use a supported iOS, Android or Windows device with a compatible ENET connection.
Exact support is based on the connected ECU—not the vehicle badge alone.
Use Check Support before purchasing. This prevents choosing a license or map before the app has identified the vehicle software and unlock requirements.
BMW M340i B58 Tuning
B58 ECU Flashing from the MG Flasher App
The BMW M340i combines the G20 or G21 platform with BMW’s turbocharged B58 inline-six engine. On a supported ECU, MG Flasher provides an app-based workflow for identifying the vehicle, selecting a compatible calibration, flashing the DME and accessing supported tuning and diagnostic functions.
Map availability, output, fuel requirements and advanced features depend on the exact ECU software, selected calibration, vehicle condition, hardware and license. The connected app remains the final source for vehicle-specific support.
BMW M340i Maps
Stage 1, Stage 2 and Stock ECU Options
The available map list is generated for the connected vehicle. Choose only a calibration that matches the required fuel, hardware, ECU software and vehicle condition.
01
Factory SoftwareStock
Restore supported factory ECU software when required through the MG Flasher workflow. Unlock state and restoration behaviour depend on the exact ECU.
Factory calibration path02
Stock or Near-Stock HardwareStage 1
A supported Stage 1 OTS map is selected according to the available fuel grade, ECU software and map package shown for the connected M340i.
Fuel and support dependent03
Compatible Modified SetupStage 2
A supported Stage 2 calibration can require specific hardware, fuel and legal-use conditions. Follow the requirements displayed for the exact map before flashing.
Hardware and regulation dependent
Power Figures
Publish verified “up to” values only.
Output varies with the map version, fuel, hardware, dyno method, environment and vehicle condition. Fixed horsepower or torque gains should not be promised for every BMW M340i.
Before Flashing
Match the Map to Fuel, Hardware and ECU Software
A stage name alone is not enough to select a calibration. Review the complete setup before flashing an M340i.
Correct Fuel Grade
Use the fuel type or octane specified for the selected calibration.
Required Modifications
Install and verify any hardware explicitly required by the selected map.
Healthy Baseline
Resolve faults, maintenance issues and charging-system concerns before flashing.
Correct ECU Version
Use Check Support to confirm the compatible map and unlock workflow.
Recommended Connection
Connect the BMW M340i through ENET WiFi
ENET WiFi is the recommended connection method for the MG Flasher mobile workflow. Plug the adapter into the vehicle’s OBD port, connect the supported device and use the app to identify the ECU before purchasing or flashing.
✓Recommended for supported iPhone and Android workflows
✓Reduces the risk of mechanically disconnecting a cable
✓Works with MG Flasher compatibility, flashing and diagnostic workflows
Choose Your Setup
How Do You Want to Connect and Flash?
Select a method to update the BMW M340i setup process shown below.
BMW M340i Flashing Process
From Compatibility Check to Verified Flash
Recommended ENET WiFi workflow for a supported BMW M340i G20 or G21.
Compatibility
Check the M340i ECU
Connect the vehicle and identify ECU software, security, unlock requirements and available products.
Connection
Connect through ENET WiFi
Use a compatible adapter and supported device to establish communication with the vehicle.
Preparation
Prepare the Vehicle
Maintain stable battery voltage and switch off unnecessary electrical loads before flashing.
Map Selection
Choose the Correct B58 Map
Match the map to fuel, hardware, ECU support and intended legal use.
Flash & Verify
Complete the Guided Flash
Follow the app instructions, allow the process to finish and review the vehicle after completion.
BMW M340i Features
Maps, App Controls, Logging and Diagnostics
The exact feature list is generated from the connected ECU and installed software. These pages explain the major MG Flasher functions that may be available on a compatible M340i setup.
01
OTS Maps
Review supported Stage 1 and Stage 2 map workflows for compatible vehicles.
Explore OTS Maps → 02Switchable Maps
Change between valid map slots without a full reflash where supported.
Explore Switchable Maps → 03Live Control
Adjust supported On-The-Fly settings directly from the connected app.
Explore Live Control → 04Vehicle Logging
Record supported engine and vehicle data for review and troubleshooting.
Explore Logger → 05Car Diagnostics
Read ECU information, diagnostic trouble codes and supported service functions.
Explore Diagnostics → 06On-The-Fly & Custom Code
Learn how compatible DME software enables advanced controls and integrations.
Explore Custom Code →
Not every feature is available on every BMW M340i.
Availability depends on ECU software, Custom Code version, map package, hardware and license.
License & Map Selection
Check Support Before Choosing an M340i License or Map
A flashing license is required for supported ECU flashing. OTS maps and packages depend on the exact vehicle. Connect first with compatible ENET hardware, run Check Support and then choose the product shown for the identified BMW M340i.
Legal & Responsible Use
Review Terms & ConditionsVerify Local Rules Before Flashing or Using a Feature
Vehicle tuning and software modifications can be restricted by emissions, noise, road-use, insurance or motorsport regulations. A compatible feature or map does not confirm that it is legal for public-road use in every location.
Follow the fuel, hardware and operating requirements for the selected calibration. The vehicle owner and user remain responsible for legal compliance, vehicle condition and safe operation.
BMW M340i Tuning FAQ
Compatibility, Stage Maps, Unlock and Hardware
Answers to common BMW M340i G20 and G21 tuning questions.
Does MG Flasher support BMW M340i G20 and G21 tuning?
MG Flasher supports selected BMW M340i G20 and G21 vehicles. Exact compatibility depends on the connected ECU software, security level, model configuration and available MG Flasher products.
Does the BMW M340i use the B58 engine?
The BMW M340i G20 and G21 use a turbocharged B58 inline-six engine. MG Flasher support must still be confirmed for the exact ECU software installed in the vehicle.
Is a Stage 1 tune available for the BMW M340i?
Stage 1 OTS maps may be available for a supported M340i. The connected app shows the compatible map list and required fuel for the identified ECU.
Is a Stage 2 tune available for the BMW M340i?
Stage 2 maps may be available for compatible M340i configurations. Use only a map that matches its stated hardware, fuel, ECU and legal-use requirements.
How much power does an MG Flasher M340i tune add?
Output depends on the exact map, fuel, hardware, vehicle condition, environment and measurement method. Use only verified “up to” figures supplied for the specific calibration; one fixed gain cannot be promised for every M340i.
Does a BMW M340i require an ECU unlock?
Unlock requirements depend on the DME software and security level. Connect with MG Flasher and run Check Support to identify whether the ECU is ready for OBD flashing or requires an external unlock service.
Can I flash a BMW M340i from a phone?
Yes, on a supported setup. MG Flasher supports compatible iOS and Android devices using an ENET connection. A Windows app is also available for supported desktop workflows.
What hardware is required to connect an M340i?
A compatible ENET WiFi adapter is recommended. A wired ENET cable can be used as a legacy fallback with a compatible device and the required network hardware.
Can I return the BMW M340i ECU to stock?
Supported stock-restoration workflows are available through MG Flasher. The exact result, unlock state and procedure depend on the connected ECU and its previous unlock method.
Which MG Flasher features are available for the M340i?
Feature availability depends on the ECU software, map package, Custom Code version, hardware and license. Connect the vehicle to see the exact list supported by that configuration.
BMW M340i G20 / G21
Check Your B58 ECU Before You Buy
Download MG Flasher, connect through compatible ENET hardware and identify the exact maps, features, unlock requirements and license options available for your BMW M340i.