So my iPhone 4 had been jailbroken for probably almost a year and everything has been smooth sailing I love it. Just the past 3 months or so my iBooks is complete garbage. Reading clash of kings and the app just crashes. Can't stay on the book for more than a minute. Thinking of unjailbreaking.. Meaning I just plug it into iTunes and update ill lose te jailbreak? What else would I lose? Any app, music, photos, contacts?