Hi, I'm a beginner with MACs/Hackintoshes and new on this forum.
I've used this method with Migration Assistant successfully. I've started with 10.10.1 running in Virtualbox where iCloud is working. And migrated my user account from virtualbox to my AMD hack.
The funny thing is that iCloud works on virtualbox with a fresh yosemite install. I've checked "nvram -p" on virtualbox and there's no MLB/ROM set (iMessage doesn't work, iCloud does).
So I've tried to copy the identity from the virtualbox to my amd hack (serial, uuid). But the apple services keep reporting that "this mac can't be identified" for the amd hack. No such issue for virtualbox. As the OP has said looks the kernel is playing a large role in getting iCloud working.