It will keep ii in place with rotation lock yes. But restrict you from using landscape option. On the "inorotate" application it gives you a few seconds to rotate to portrait or landscape after you open up the application and THEN it locks it down which is kind of nice if you prefer a landscape view for the nav. Also it allows you to specify which programs you want to lock down and which you want to allow to remain landscape/portrait capable. BUT it only allows you to do that to the following programs: ipod sms/mms mail safari notes contacts all the other apps on the phone are a blanket restriction (like the included option on iOS4) But yes, thank you for bringing that up, the rotation lock does work effectively for eliminating the portrait/landscape flip/flop AND no jailbreak is required.