i got mine from thanksbuyer.com .. and the only reason i went for it is the minnaza can't handle more than 4s batt , where the N1/2/3 support upto 6s . and i'm glad i did , cuz i really like the DJI now called iosd interface
i did lil diggin' on some chinese sites and i found the firmware v.1.6 for the N osd's .. the link below has 2 zip files the first one is for the normal N osd the ones we have .. the 2nd zip file seems to be for the new mini osd that comes in a tiny aluminum case.
link :
非凡科技升级软件_免费高速下载|百度云 网盘-分享无限制
the update seems straightforward , here's a chinese clip on how to make your FTDI connection and do the upgrade .
极翼P2飞控加装非凡FFOSD N1版的方法_高清—在线播放—优酷网,视频高清在线观看
pls note that i haven't tried any of the above , i'm just trying to help here..