BMW 328i F30 N20B20 ECU File – MEVD17.2.4 525600 / 9BCGAJXD (P2011 Delete Included)

Data size 2mb not correct for internal flash N20i (4mb).
How to use it ?

mrguru said:

Data size 2mb not correct for internal flash N20i (4mb).
How to use it ?

Click to expand...

Good observation. Let me clarify both points:

File Size

You're right to question the 2 MB (2,097,152 bytes) size. The MEVD17.2.4 on the N20B20 has a 4 MB (4,194,304 bytes) internal flash (TC1797 processor). A full read via Auto Tuner OBD or bench should produce a 4 MB binary.

However, a 2 MB file from Auto Tuner is not necessarily wrong — Auto Tuner in OBD mode on MEVD17.2.x typically reads/writes only the calibration area (2 MB), not the full program flash. This is the standard working area that contains all maps, DTC tables, and tuning-relevant data. The remaining 2 MB is program code that doesn't change between stock and tuned.

So the 2,097,152 byte size is consistent with an Auto Tuner OBD partial read (calibration zone only), not a full bench dump.

How to Use It

• Read tool: You need Auto Tuner (Alientech) — the file was read and is meant to be written back with the same tool via OBD.
• Do NOT try to flash this 2 MB file with a different tool (e.g., KTAG bench, CMD, etc.) that expects a 4 MB full dump — it won't match the memory layout and you risk bricking the ECU.
• Workflow:
  1. Connect Auto Tuner to OBD port
  2. Select BMW → MEVD17.2.4 → OBD protocol
  3. Read your stock file first (always keep a backup)
  4. Write the desired variant (Stage 1.1 or Stage 1.1 + P2011 delete)
  5. Clear adaptation values and let the ECU re-learn

Important: If your car's SW version is not 9BCGAJXD / 525600, do not flash this file directly. The software version must match exactly, otherwise you'll get mismatched calibration data against the program code. Verify your SW version with an OBD read or ISTA before flashing.

i have no auto tuner, only ACDP, can i get refund or free change to other one similar but 4mb
?

mrguru said:

i have no auto tuner, only ACDP, can i get refund or free change to other one similar but 4mb
?

Click to expand...

That's a purchasing/refund question — I can't help with that since I'm only here for technical support. You'd need to contact the seller directly or use the forum's product support/messaging system for refund or file exchange requests.

However, on the technical side, here's what matters:

ACDP + MEVD17.2.4 Compatibility

The Yanhua ACDP with the BMW DME adapter (Module 27) reads MEVD17.2.4 via bench mode and produces a full 4 MB dump (4,194,304 bytes) — internal flash including both program and calibration areas.

You cannot flash a 2 MB Auto Tuner calibration-only file with ACDP. The memory layout and addressing are completely different. Attempting it could brick your DME.

What you would need:

• A 4 MB full binary tuned file matching your exact SW version (9BCGAJXD / 525600)
• Or — take your own 4 MB ACDP bench read, and have a tuner apply the Stage 1.1 + P2011 calibration changes to your full dump using WinOLS (map transfer from the 2 MB file into your 4 MB binary)

The second option is technically possible if a tuner knows the map locations, but it's not a simple drag-and-drop — it requires proper WinOLS map matching between the partial and full file formats.

So to summarize: the file as-is is not compatible with your ACDP workflow. Reach out to the seller about your options.