The problem

You buy an original file, connect the programmer, try to write it - and the device refuses. That doesn't mean the file is bad. It means it doesn't match what your tool is currently expecting.

This applies only to ECU files in the form of a raw memory read. Files VAG in the FRF and SGO format, Jaguar Land Rover VBF files, and CAT files are uploaded directly, without any extra steps.

The read method matters

The same controller can be read in several ways - through the diagnostic socket, on the bench via the connectors, or through the bootloader. Each method produces a file with a different layout and a different length.

A file from the database comes from a specific method. If your device works with a different one, it expects a different format and will refuse to write.

Calibration area

Inside the controller's memory, data is split into sections. The calibration area is the section that holds the maps and parameters - and that is usually what the whole operation concerns.

The practical solution looks like this: you make your own read from your controller, and transfer the calibration area from the purchased file. You get a file your device will accept, with the data you came for.

Checksums

Controllers verify the consistency of their contents. After every change the checksums must be recalculated, otherwise the write will fail or the controller will report an error.

Map editing tools usually do this automatically for popular designs. With rarer controllers, it may need to be done separately.

Two options

Do it yourself

If you work in WinOLS or a similar tool, transferring the calibration area and recalculating the checksums is routine. The data you paid for is complete in the file.

Have us do the matching

We do it free of charge. In reply to your order message, send:

• a read from your own controller, made with your device, before any changes,
• the name and version of your programmer,
• the read method,
• your order number.

We send back a file ready to be written by your device.

What not to do

Don't force-write a file when the device reports a mismatch. With a non-matching calibration area the write will usually abort, and in the worst case the controller will need recovery in bootloader mode.

Unsure which file to choose? Start with the list of controller families or write to us with the numbers you read.