This guide details advanced software-based methods for replacing the Individual Serial Number (ISN) in modern Bosch MG1 and MD1 ECUs using Tool32. This serves as an alternative to direct EEPROM hex editing and is intended for experienced users only.

Disclaimer: This is an expert-level procedure. Incorrect commands or a flawed process can permanently lock or damage your DME. Proceed with extreme caution and at your own risk. Everything will become clear if you read carefully.

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Required Tools & Software

• A BMW diagnostic interface: ENET Cable or ICOM.
• BMW Standard Tools installed on your PC (specifically, Tool32).
• The required PRG files (e.g., `DME_BX8.prg`) or projects for Tool32.
• The ISN from the original vehicle's security system ("new ISN") and the ISN from the donor DME ("used dme isn").

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Method 1: The General `DME_BX8.prg` Procedure

This method is a common way to replace the ISN using a specific Tool32 job file.

Step 1: Load Program and Job

1. Open Tool32 and load the DME_BX8.prg file.
2. In the "Jobs" list, select the job named steuern_ews4_sk.

Step 2: Unlock the Donor DME

1. In the "Arguments" box, enter the following command, replacing `(used dme isn)` with the full ISN string from the donor DME you are working on:
   
   Code:

   UNLOCK_CLIENT_SK;(used dme isn);DME

2. Press F5 or click "Run job" to execute the command. This will unlock the ECU for writing a new ISN.

Step 3: Write the New ISN

1. After the DME is unlocked, you must execute the following four commands one by one.
2. For each command, replace `(new isn)` with the full ISN string from the original car's security system (e.g., from CAS or FEM).
   
   Code:

   WRITE_CLIENT_SK;(new isn);DME
   WRITE_SERVER_SK;(new isn);DME
   LOCK_CLIENT_SK;(new isn);DME
   LOCK_SERVER_SK;(new isn);DME

3. After executing all four commands successfully, the new ISN is written and the DME is locked again. The procedure is complete.

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Method 2: EWS5 System Considerations & Additions

For newer vehicles with EWS5 security, the process may require additional steps and checks.

1. Reading the ISN:

• Read the ISN from the original OEM dump. This may require converting the value from hexadecimal to decimal format.
• Open Tool32 and load the appropriate project (e.g., DME8FF).
• Run the job `status Lesen -> ARG;EWS_DME_LESEN`.
• In the results, check the value for "STAT_ISN_PRESENT". On a non-resetted ECU, this value will be `01`. After a successful reset, it should read `00`.

2. Final Steps with E-Sys:

• After the ISN work is done in Tool32, you must flash and encode the new DME using E-Sys.
• It may be necessary to disable all FSCs via the FSC tab and change the VIN in the VCM before flashing.

3. Working Hours and Transmitter Input:

• Resetting engine working hours is a separate procedure, which may require a specific `.TST` calculator file.
• Important: Pay attention to the "Transmitter input" value. This often depends on the master/slave configuration of the original keys. For example, if the master key is 12, the slave may be 13. You must read this value from your original DME and write the same value to the new DME. After writing, use the `ARG;EWS_DME_LESEN` job again to verify the value is `00` instead of `01`.

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Final Words

These procedures are complex and require a deep understanding of BMW systems. Everything is made clear through careful reading and logical steps. Do not perform "crazy" actions.