Currently on iOS 9.1, iPhone 6s Installed biteSMS (8.0.3 I think) via Cydia to see if it will work and after respring, I got stuck in boot loop screen. Restarted the phone, no luck, still stuck. Cannot restore on Itunes to 9.1 b/c those are not longer signed as of December. The error is b/c of biteSMS and I'm wondering what I can do. Tried editing hosts file, no luck. If all else fails, I'm guessing I'll have to restore and update to 9.3.1 :( Any help appreciated.
If you want to avoid having to restore your phone just in order to remove a bad cydia tweak, turn off the phone. Turn it on and as soon as Apple logo appear, hold Volume Up button until your phone boots. It might not work for everyone and for some folks, Volume Down works as well. If nothing works, unfortunately, you will need to restore.
BiteSMS's latest version only supports up to iOS 7, so you'll have to remove it (obviously). It's strange that your device didn't just boot into Safe Mode but anyhow all you need to do is boot the device holding the volume down button and it will boot without Cydia Substrate, then remove biteSMS.