The JPG save is done in the Canon firmware and nobody has discovered a way to disable that.
To be pedantic (this is the internet after all
), srsa_4cs filewrite stuff can be used to do this so a way has been discovered, it just hasn't been implemented in the trunk yet. It also needs new code for each camera.
We could add a "raw only" option when this stuff goes into the trunk, but it's not really clear what the benefit would be. It happens at the end of jpeg processing so the time saving will be very marginal. If you are worried about space, you could just choose a small jpeg resolution. The camera will still waste some resources for every shot because it thinks it wrote a jpeg. You also obviously wouldn't be able to review your pictures (possibly including recreview, I haven't checked that)
@FaKK
What benefit do you expect to gain from disabling jpeg?
