issues trying to root after restoring with flashtools

ok so I have a vs985 that was rooted with twrp and was running stock 4.4.2 10b. Ive been on it for a while and wanted to update. went though my usually backup routine, then updated base band to 23c installed cyanogenmod 12.1 then went to install gapps but when it started it rebooted back in to twrp so I tried again with no luck same thing, so I figured I'd boot the phone and go out and grab a new download reboot into recovery and install gapps, but after rebooting wasn't able to boot back into twrp. for some reason the button combination wouldn't work nor an apps I downloaded from the browser as I didn't have play store. either way I was able to get into something that allowed for a safe mode and reboot but that was all. so I said ok I use recovery tool to flash 10b root then install twrp then same as before update modem, cyanogenmod then gapps, but after going back to 10b I was not able to get root using stump root as I had before. every time I tried loading the app and I got an error saying something about phasing and everything I tried I was able to get it to load. so I thought maybe I could run some updates and try and root from other methods and so far no luck. so I'm currently on 5.0.1 and still cant root this methods like lg one click root so others. any ideas why this is happening? I don't mind going back to 4.4.2 10b to get root but I've had no luck with the multiply stump root or others I've tried.

thanks
Andrew