It's unlikely, but there is the odd chance that the previous owner of your phone saved their blobs. 1conan backs up blobs to his server, you can try to access them by going to https://tsssaver.1conan.com/shsh/[YOUR_ECID_HERE]/Maybe you'll be the lucky one who gets their chance to downgrade! #AND IF YOU DON'T HAVE BLOBS, START SAVING THEM NOW. IF YOU SELL YOUR PHONE, TELL THE BUYER THAT YOU HAVE BLOBS.
1.Jailbreak with load Tweaks turned off2.Enter iCleaner Pro -> clean and Respring. That’s it. Works like a charm for me.
Note: I backed up on the same version)So I used rollectra to erase my phone and to remain real, the 1st time, I set it up normally, then I clicked restore backup on iTunes. Then afterwords, my phone booted up to the setup screen, I unlocked my phone and it said “press home to upgrade”, then I was like what? I was looking for bypasses but I didn’t find anything, I just said ok hello 11.4, then I clicked press to upgrade and put in my passcode, afterwords another setup screen came, it setup my iCloud and all, then after that screen, I want to settings general and about and I saw 11.3.1, I was jumping all over the place that I saved my jailbreak.So if you see that screen it won’t update your phone.