I can't open my iPod U2 cause of dead battery so I try to open without any pre-information so I cut the hold switch button cable :/ but thanks to iFixit I cover both of them.
It was pretty smoot. With little information about iPod U2 things got easier and easier. It took about 30 minutes. Bad thing about Headphone Jack is there is no coulor option so its look little bit non-original on iPod U2
Don't use any extreme force.