Have you tried it? It's all eprom? I understand there are updates on his software/firmware. I was just wondering HOW? Software, Firmware, or Hardware, and can you save and or have more than one upgrade option?

Pre 58 options and or. I have some pre WWII Japanese 30cm records (not vinyl) weird EQ and RPM.. I think they are 16 rpm 12" (very close).

I'm tinkering, I just don't want to spend a fortune. BUT if it is a nice Phono stage anyway.. Maybe I can get a twofer.. LOL  I've done my share of compiling, and altering code... Use to hate debugging someone elses MESS.. I'm just a mechanic...

Regards
I have a Puffin in one of my secondary systems and am currently using it with my VPI Classic 2 / Van Den Hul MC-Two Special cart. 

I've tried a number of budget phono stages and haven't seen one that came close to the Puffin, I have a Jolida JD9 II that got relegated to a rarely used system and sold both of my Musical Surroundings Nova Phonomena phono stages, if that tells anything.  It's not quite in the same league as my Manley Chinook or Pass XP-15, but they don't leave it in the dust and cost a few times what the Puffin does.  Both of those have a little more "body" than the Puffin, and more flexibility in terms of loading options.  The Puffin however, has more gain settings than most phono stages.

The Puffin has a lot of flexibility, but I think it sounds best with all the controls neutral.  Updating is easy and it's cool that Shannon is always tinkering and adding new stuff, like the "Magic" feature to minimize pops and tics.  I don't use it, because I use this system for play grading records, but it works.  It won't completely eliminate all noise, but quiets things down and doesn't seem to degrade playback.  He's also pretty easy to get in touch with if you have questions and is super passionate about what he does.

I recommend it to anyone that's looking for a phono stage under $1K.
It's firmware. You can save them all and use any one you like. No reason to go backwards though.