Where the problem comes from

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

This applies only to ECU files in the form of a raw memory read. Files VAG in FRF and SGO, Jaguar Land Rover files VBF and files CAT can be uploaded directly, with no extra steps.

The reading method matters

The same controller can be read in several ways — via the diagnostic socket, on the bench via the connectors, via 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

In the controller's memory, data is divided into sections. The calibration area is the section where the maps and parameters reside — and it's usually what the whole operation concerns.

The practical solution is this: you make your own read from your controller, and from the purchased file you transfer the calibration area. 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 be necessary to do it separately.

Two paths

Do it yourself

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

Have us match it for you

We do this 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 reading method,
• your order number.

We'll send back a file ready to be written with your device.

What not to do

Don't force a file in when the device reports a mismatch. With a non-matching calibration area the write will usually stop, and in the worse 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.