@Shock

Is a well known fact that everytime a JB is required, it wipes out everything.

Proceed to do a manual backup of your sms, notes, video files etc and SSH back those files after JB.

@Bernard Yeo

Just backup the db files and set it back to the same location. I did this v my 2G iphone and transfer those db files over to my curent 3G iphone. All good.

As for restoring, is recommended that you're on Fw 2.1 which you already know and i'm not sure how safe it is to JB your phone with your curent existing Fw. You can give it a go and see what's the outcome. If not, just ask Hanxz as he is facilitating an iPhone Community Service thread.

http://forum.lowyat.net/topic/826183