Not available elsewhere, right now, the last Rom revision for the S-770 Sampler.  S750 turbo also available but specify if you wish for this.

This will improve speed of menu redraws and optimizes midi timing.  The original Rom was on 128k chip so the code has been significantly expanded.  You just remove the old EPROM and insert this, the correct way of course.

To get the whole turbo treatment you need to upgrade the CPU and the clock - can talk you through how to do this, if you so desire.