as the title says.. I got it with 3.1.2 and i updated to 4.1 back in the day. I never restored it but using Shift-UPDATE!(i think it was limerain).. so all of my stuff was kept on the device. I have more than 4000 music files and i converted them to 128 AAC(in the iTunes options) and i don't want to convert them again. so, will i be able to JB if i shift-update instead of shift-restore? thanks.