iPad air wifi iCloud bypass hardware problem

i tried to remove iCloud on iPad air wifi. i have changed the band ic with an iPhone 5 iCloud locked nand ic. everything was good. i could restore the device as normal. iTunes detected the iPad as iPad air 16 gb. but as i wanted to activate the device after selecting the country it says connect to iTunes. i connect to iTunes it says there is a problem with your iPad. do anybody have any idea why it is just like on iPhone 4s after wifi ic not work and we could not activate. what do you think is it not possible to remove iCloud changing the nand or did i do something wrong.