is it safe to jailbreak ios 8.1.2 if my device was upgraded on wifi?

i have an iPhone 5 running ios 8.1.2 and i have heard that i would run into problems if i jailbroke it and it had not been updated using itunes on a computer. the signing window is closed so there is no way to keep ios 8.1.2 if i restored it using itunes. is there a way around the problems? and if not, what are the problems and how can i patch them?