I am using My grand running ios7!
It was so easy I just downloaded it..
Its 1-2 Gigas only tho!
I Was at Android, then windows then iOS7..
Okay here we go..
Steps to get the System :
1- open http://youtu.be/JmvCpR45LKA
2- Choose the system you want, windows, iOS... Etc...
3- Download it.
5- you are done
Hit Thanks if helped!