PS Audio have released version 3.0.6 (Snr) for Snowmass OS, the changes in the update are for the PIC code only, so in theory there should be no effect on SQ.
I was on version 3.0.0, I didn't update to 3.0.5 when released, in my system there is a considerable difference between 3.0.0 and 3.0.6.
The later has crisper highs and slightly more pronounced mids, making it a bit bright first up, the bass seems to be better defined, but have less impact, its more in the background, soundstage is slightly improved. After a couple of hours listening last night I think I prefer 3.0.0, I will give it some more time to get use to the change before reverting back to 3.0.0 for a final comparison.
From the PS Audio forum:
There are two parts to the software puzzle in the DirectStream DAC. The first is Ted’s code in the FPGA. This is what makes the firmware a new mountaintop and where the major improvements come from. Ted is normally tackling big pictures improvements in how jitter is handle and how the data is processed.
The other part of the puzzle is the PIC code. This is the code that lets the FPGA interface with the screen and the other bits and pieces of the DAC outside the FPGA. It’s the mundane stuff that makes the DAC usable.
3.06 (and the other 3.0x firmwares) are updates only to the PIC.