firmware spoofing problem

Nayab Hussain

okay so i was on ios 9.3.3 and jailbroken and i wanted to spoof my ios version i used the ifile thing by changing my ios version restarting and it was spoofed to ios 10.2 but the thing is i didnt think of this before becouse its a tethered jailbreak im stucked in 10.2 now i can jailbreak again because pangu says its 10.2 i have cydia and everthing but i cant access them is there a way to go back to 9.3.3 or restore back like cydeia eraser do or something.. i did try yalu by it crashes when i press the go button