Won't work for me, just tells me I am "at the furthest location across all devices" when I try to sync a book between my iphone 4 and my k3

Calibre is all up to date and I have tried reconverting books until I am blue in the face.
Am I doing something wrong? I must admit I did not try the sync on a non-amazon book before the v2.6 update.
My phone is jailbroken, so it's possible for me to revert to an older version of the app if absolutely necessary, but I would rather not...
:EDIT: Seems to have sorted itself out all by itself...strange! Still, all works now so I am chuffed!