I was not aware of this. I can't find a link to the upgrade on the Sandisk web page and would appreciate it if you could provide a link.
That said, I own the Sansa 1GB version, and love it. Aside from a couple of minor flaws, it's perfect for me.
I reviewed it on Epinions in detail, and you might want to take a look, to see if it matches what you're looking for:
What do you guys think? After a lot of research I think the main difference betweeen these two players is that the extra money you would pay for the iaudio g3 is for the ogg support... is it worthy? Regarding sound quality, it seems that the problems reported for the sandisk fix after a firmware upgrade...