Since you have TWRP installed, hopefully you made a back up of the original system, or your KK rom and you can just restore the image through TWRP recovery. If not, download one of the ROMs again, place it on sd card, and reinstall the rom. I guess if that doesn't do the trick you can look up how to restore through kdz. I have not needed to do that ever but have seen posts about it.

good luck.

 

Agreed with the post from mn 1968. Twrp also should have USB OTG support where you can download a rom and then flash it through TWRP recovery and it should also support sideloding ROMs from your PC to your TWRP recovery while connected to your PC in recovery mode.

If the above methods don't work then you may want to try the unbrick method described here - http://androidforums.com/tmobile-optimus-f6-all-things-root/776738-guide-how-unbrick-unroot-complete-stock-updated-11-20-a.html

Hope this helps and good luck. If you need any help just let us know.

 

this worked well for me
http://androidcreations.weebly.com/root-and-2nd-init-cwm-recovery.html

 

What did you do? "Reboot bootloader"? XD

It's a known thing with locked LG Bootloaders. It will write over your whole Internal Storage with 00. I have the advanced power menu in xposed and I have confirmation enabled, since "Reboot bootloader" is in the list.

 

Go to root forums section look for the kdz method take 15-30/mins or so to download the kdz provided and the installer. Look for it. I think gt also has on his site a short version with the downloads and instructions. It's not that difficult. You just have to read

 

Here's the kdz method frosthax1 is referring to...

unbrick/factory restore

 

In addition, don't use UpTest, since it seems to crash out on Windows 7 and above when you try to flash either way. UpTestModwin contains a Trojan. You can flash 12b by going into download mode and using the default LG Mobile Support Tool. YES, THEY FINALLY FIXED IT!

Download mode is hold just the volume up button from a powered-OFF state, then plug the phone into the computer. You'll get a gray box that says download mode and the drivers will install.

Don't start flash in normal mode. It fails, and remember to restart your computer after installing the drivers. New driver version is 10.1.

Use "Upgrade Recovery" from the options menu, since the normal method doesn't work if you are rooted.

http://www.mylgphones.com/lg-software-tools-download

Edited: Do I have dyslexia? XD

 

Towelroot, then install this for recovery.

Towelroot - https://towelroot.com/tr.apk
Recovery - http://oudhitsquad.com/pressy4pie/F6/F6Utilities2.apk