hi,
i have recently jailbreaked my iphone with sn0wbreeze
when i turn on my iphone, it s stay freezing on the startup screen with , and restart after a while,
i can only boot it using ibooty
That's because its a tethered jailbreak. Use a search engine of your choice to search for "tetherd jailbreak" and read about it. Or use MRoogle to search MacRumors for many other threads about this subject.