Sony's lossy RAW compression was explored at length in a thread
here last year.
Have we learned any more about the ASICs and imaging pipeline since then, as to be able to hazard a guess as to whether a firmware change to the A7RII could offer a lossless RAW compression mode, even if it comes at the expense of speed?
To this point, Sony has indicated that the A7RII will use the same lossy compression as previous cameras, although supposedly the leader of their mirrorless group has indicated that a firmware change
could rectify this shortcoming.