Manually Replacing ISN in MG1/MD1 ECUs via EEPROM

Nate_B · 05.01.2026

Bin said:
Bin submitted a new resource:

Manually Replacing ISN in MG1/MD1 ECUs via EEPROM - A step-by-step tutorial for cloning the ISN to adapt a used MG1/MD1 DME.

Read more about this resource...

When doing this procedure, I have read that the MD1 and MG1 DMEs made after mid 2020 have different security, making them unable to be written. How do you write to these DMEs? And does this process of writing prevent the vehicle from passing smog? The company in Netherlands that unlocks these ECUs for tuning cannot prevent the smog test machines from seeing the modified CVN files, failing the smog test.

Bin · 06.01.2026

Nate_B said:
When doing this procedure, I have read that the MD1 and MG1 DMEs made after mid 2020 have different security, making them unable to be written. How do you write to these DMEs? And does this process of writing prevent the vehicle from passing smog? The company in Netherlands that unlocks these ECUs for tuning cannot prevent the smog test machines from seeing the modified CVN files, failing the smog test.

You’re right — post mid-2020 MG1/MD1 have newer Bosch security, so you generally can’t write them the “old” way. In practice it requires a paid bench unlock service (yes, the expensive ones in EU/NL, etc.), and there’s no public DIY method I can share.
About smog/CVN: if your inspection checks CVN, any tune will change it and it can be detected. Legal pass = stay stock or flash stock back for the test.

v-snejok · 19.02.2026

after changing isn in eeprom and flashing via e-sys isn changes back, seems like some checksums need to be calculated?

mrguru · 30.07.2026

stickly followed this guide and cross checked ISN on donor DME after change but why car G20 MG1 only lock/unlock, can not start engine ?

XXAnder · 05.08.2026

mrguru said:
stickly followed this guide and cross checked ISN on donor DME after change but why car G20 MG1 only lock/unlock, can not start engine ?

This method worked only on SPC577 processors

Bin · 05.08.2026

XXAnder said:
This method worked only on SPC577 processors

Which one do you need?

XXAnder · 05.08.2026

Bin said:
Which one do you need?

MG1 TC298P

XXAnder · 05.08.2026

Bin said:
Check https://bmw-az.info/paid-apps/

Here soft from AZ, but for DME with TC298 it dont work, what is stated in AZ about EWS5 DME is fake. I already write in discussion in topic. Maybe some info in pdf downdoad.pdf but i cant downloaded it.

Thread 'Replacing MG1/MD1 ISN with Tool32'

02.07.2025

Bin submitted a new resource:

Replacing MG1/MD1 ISN with Tool32 - Expert-level methods for ISN replacement in MG1/MD1 using Tool32 jobs.

Expert-level methods for ISN replacement in MG1/MD1 using Tool32 jobs.
View attachment 160
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...

Manually Replacing ISN in MG1/MD1 ECUs via EEPROM

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