I would recommend not writing to an ECU until you have a confirmed good backup copy of the data.
If I have done the ECU modification for you then I will have sent this file to you.
It is a good idea to save separate copies (versions) of your tune to the computer as you make changes, then if you every want to go back to a previous version it will be easy to roll back. You could name them starting with a version number that increases for example.

If your file won't load or you have some other problem then send me a copy of your file and an explanation of the problem - james@rovermems.com
There are definitions for some specific ECUs at the moment so for any others I will need to add the definitions which doesn't take long, just send me your bin file over

Once you have loaded a file, you can edit the tables/maps, save buttons will appear in the top right of the screen.
The 3D graphs do not update until you reload a file, so save and re-load if you want to see the new graph, they will automatically update in a future update.

Checksum
It appears that the 2J ECUs run without actually checking the checksum, so it is not needed to correct this.
I have added a button which can correct the file checksum after you make changes if you like.

Please wait... Progress / Bytes

It looks like you were already connected to the ECU.

Do you want to resume editing where you left off (much slower),

or start again fresh (lose unsaved changes but fast)?

Please wait, saving changes permanently to ECU
This should take around 1 second, if nothing happens then something has gone wrong

Failed saving changes to the ECU

Connecting to ECU, please wait
This can take approx 5 seconds the first time
Once connected, the calibration will be downloaded

If this is not working then try switching off the ignition for 15 seconds and then try again

There has been a serious problem, you could press F12 to see the main console output