The source of the problem

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 dump. VAG files in FRF and SGO format, Jaguar Land Rover VBF files and CAT files are uploaded directly, without any extra steps.

The reading method matters

The same controller can be read in several ways — through the diagnostic socket, on the bench via the connectors, or 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 another one, it expects a different format and will refuse to write.

Calibration area

In the controller's memory, the data is divided into parts. The calibration area is the part where the maps and parameters are stored — and this 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 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.

Commission us to do the matching

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

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

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

What not to do

Don't force the file upload when your device reports an incompatibility. With a mismatched calibration area the write will usually abort, and in the worst case the controller will require recovery in bootloader mode.

Not sure which file to choose? Start with the list of controller families or write to us with the numbers you read.