Hi,
I need my app only run on iphone4, iPad and ipad2
Where should I specify this ? Xcode? Unity? iTunes connect?
Thanks for helping me.
Anyone ?
Set cpu to arm 7 and then in itunes connect, select the devices it works with in the options where you submit your title. You have to submit to do this. You do not have to upload a binary though or go through with the process.
Its not possible to limit the game to specific devices at all.
Thats illegal and will not be tolerated by apple, they have no interest in having another Nokia / Android alike platform with applications that run on 3 devices for artificial / lazyness reasons but not on the others although they could with little work.
You can limit the game to specific hardware capabilities but only if you make significant use of it.
For the limitation you want to do there is no hardware limit that would grant that at all.
For iPhone4 and iPad2 you could use gyroscope if you use it, but iPad1 has no gyro. In addition there is a bug with the gyro limitation that prevents ipad2 from installing it.
Also its not possible to cut iTouch4 without cutting all ipads too (cause the only way to cut itouch4 when iphone4 is present is to require phone)
You can choose to use ARMV7 or OpenGL ES 2.0 (which is 3GS + what you mention there + the itouches) or limit it to gyro and cut the iPad1
Hi guys thanks for answer.
As my game requires a large amount of memory because of large scene + textures, the game drops to 3fps on an iphone 3G.
It works perfectly on iphone4, ipad and ipad2.
I don’t have any 3GS, so i could not test it on this device. I wonder if the game would work on it.
If i wanted the game to work on any device i would have to model the word twice for old device, it could take me more time to develop 
in Unity, if i select Arm7, it’s writen Ipad only. Will it work on iphone4 and last ipod generation ?
Armv7 covers iPhone 3GS, iPod Touch 3rd generation and everything since, across all the iPhone, iPod Touch and iPad lines.
If the problem is the iPhone 3G, then you are fine going with ARMV7 only actually.
The iPad1, iTouch4 and the whole 3GS generation have the same amount of RAM (256MB) and normally the 3GS generation is actually even faster than the iPhone4, iTouch4 and iPad1 cause its screen resolution is 4 / 5.2 times smaller than the 4th gen / ipad1 devices (480x320 vs 960x640 / 1024x768) while they all have the same graphics chip. The 4th gen / ipad1 only exceed it performance wise if its related to cpu power (AI, physics, high drawcall number beyond the 50s)
the one thing you though need to check is the UI unless it was written resolution independent 
Thanks Dreamora for theses tech spec, I did not found them on internet. Hope everything would be ok!