Ok, bit of info for you: As some people may know Asus recenly released 4.2 for TF300T. We were all hoping it would give us back NVFlash but until now nobody can confirm and rayman (NVFlash dev) ment if there would be news they would be posted. As there are no news until now I think Asus didn't change anything for NVFlash in the new bootloader.
At the mails we were writing they always responded "It's too dangerous for the users" (not many times) or "We'll forward this to our dev section in Taiwan" (many times). If I got more time I'll ask them one more time telling them we have now 1'000 signatures but I don't know if this will help much... So keep on signing, if they see these people are getting more and more they will probably do something. Probably it will help even more if you write them a customer suggestion on this link: http://vip.asus.com/eservice/cus_suggest.aspx
(I'll also post this in the OP) in your language with a link to the petition
So keep it going and if I have major news they'll be posted here for sure!