Master vs slave tools explained: what they mean and what to send us
Why a read from a slave tool won't open in an editor, who can decrypt it, what that means for working with us, and exactly what you upload to the portal.
When you start offering tuning, one of the first decisions is whether to buy a master or a slave tool. That choice decides who you can work with on your files. Let's clear it up.
What a master is
A master tool reads the ECU and saves the file in a form that opens in calibration editing software. Its owner can edit it themselves or send it to whoever they like. It is the choice for people who write their own calibrations.
What a slave is
A slave tool reads and writes ECUs just like a master, but the files it saves are encrypted. It is linked to one specific master, and only that master can open its files, edit them and encrypt them again so the slave can write them.
In practice, a slave is a tool for workshops that want to offer tuning without their own calibration team. You do the read and the write; your partner with the master writes the file.
Who can decrypt
Only the master your slave is linked to. That means:
- If your slave is linked to our master, you send us the encrypted file as it is, and we return a file ready to be written with your tool.
- If it is linked to another master, we cannot open the file. Please don't send it hoping we will "find a way".
- A slave is normally linked to a master at purchase or activation. If you are thinking of working with us on a slave tool, talk to us before you buy or activate it.
Advantages and limits
Master: full control and the freedom to work with anyone. It needs knowledge, or a partner, for the editing, and usually a bigger investment.
Slave: lower starting cost and a clear role: read, send, write. But you are tied to your master for every file.
There is no right answer for everyone. A workshop that wants to start quickly with reliable files often finds a slave more sensible. Anyone who wants to build their own calibration know-how will go for a master.
What to upload to the portal: step by step
- At registration, list every tool: brand, master or slave, and the serial number for slave tools. That way we know from the start which format to return files in.
- On each job, choose the tool and whether it is master or slave.
- Upload the file as the tool produced it. For a slave, the encrypted file, without renaming or converting it. For a master, the read file as the tool saved it.
- Don't combine files from different reads, and don't upload a file you opened and saved again in another program.
- State the read method (OBD, bench, boot/BDM), because it affects the write as well.
The file we return is in the format your tool reads, together with the WTC (What To Check) sheet for the checks before and after writing.
Common mistakes that delay a job
- Wrong master/slave setting. An encrypted file declared as master cannot be worked on until it is clear what it is.
- A file from a different tool. If you read with one tool and will write with another, say so in the notes.
- Renamed or compressed files. Upload the file as it is, without changing its extension.
- Missing ECU details. Without the hardware and software numbers we cannot confirm the read matches the vehicle.
Which tools we work with
We work with the main tools on the market, master and slave. If you are not sure about yours, write to us before registering.
Want to get started? Register for the File Service.