Have a T-Mobile D801 phone. Took the OTA update and successfully upgraded to kitkat. Did not like kitkat so I downgraded back to 4.2.2 using the LG Mobile tool and the D801110C.kdz file. This downgrade was successful and I was able to root also with success.
So I have a stock rooted 4.2.2 phone with stock recovery.
Used the phone several weeks before playing with the build.prop file. After a modification, restarted the phone and the phone now will not boot past the LG splash screen.
The phone will boot to stock recovery as well as fully boot to download mode.
Installed newest LG mobile tools as well as the drivers, and reinstalled several times.
I have tried using the standard LG mobile tools to revert to stock. When using this method, the program identifies the phone correctly as a D801 but does not list a software version and tells me that there is no upgrade available. When click on upgrade recovery, it tells me that there is nothing to fix. So, I tried clicking on upgrade recovery without phone attached and enter the imei number and connect the phone. The software downloads the update successfully but when it attempts to install, stops at 2-3% and tells me to connect the phone. Restart the phone in download mode, reconnect and attempt again with same failure. Have tried this with swapping the downloaded file with110C, 110G, and kitkat KDZ files and all fail equally at 2-3%.
Have changed and tried com ports 41, 7, and 4 as well as disable LG modem in device manager and all fail.
Have tried this method on a windows 8 64 machine, windows 7 64 machine, and windows xp 32 machine and all still yield equal results. Tried several different USB cables and ports.
Have attempted using the KDZ with the L&D method using the 110C/D and kitkat files and the 110C/D fail at 49% and the kitkat will not even start, just errors right away. Tried this method with the different computers as well as cables and com ports.
I have also tried using the LG flash tool with the D801 TOT file and dll. Will not start and gives me error that the model numbers do not match even though it says it is a D801 at the top of the program.
At a loss here for what to try next. Any help on this would be much appreciated.