tango wrote: can i put back the original file i read and it should start?
Yes.
the basics of ECUFlash are well tested, the XML's are mostly fairly well documented/proven, it is pretty simple to get the basics correct (main fuel and ign maps).
The XML is like an index file, to tell you what each data point is relating to what ecu operation, and to convert it into some numbers that hopefully we can relate to easier.
Sure if it is wrong, you'll be changing something you shouldn't, or at least didn't want to, so untill you verify the changes, caution should be advised, hence the disclaimer.