Hi please follow the guide by gbiggie if your downgrading his guide is much more explained, updated and better and he can also assist you all the time http://androidforums.com/esteem-all-things-root/479734-guide-downgrade-ms910zvc-ms910zvb.html
UPDATE
Ok to start up thanks to user Jackpot08 a lot for posting the .TOT files and LGpnst big thanks to him.
To start off first download this files Multiupload.com - upload your files to multiple file hosting sites! (LGPNST) Free File Hosting, Online Storage & File Upload with FileServe (ESTEEM'S ZVB STOCK TOT or IMAGE)
The drivers can be obtained when you connect the esteem to the computer it will show up as a cd drive in MY COMPUTER
Since MS910.DLL does work anyway i will provide the one that works which is VS910.DLL link Multiupload.com - upload your files to multiple file hosting sites!
After your done downloading all the file extract the "LGPNST.zip" file where it will be easier for you place the MS910ZVB_01.SB_01.P3018.R1003.tot file on your desktop as well
then install..
LGPNST
LGNPSTv1.2_Store_Version.msi
LGNPST_v1.2_Lab_Version.msi
Then navigate to the folder named "Components" and install this "LGNPST_Components_Ver_5_0_12_0.msi"
Next navigate to "GenericModels" folder and from there install "LGNPST_GenericModels_Ver_5_0_10_0.msi"
Next go back to the original folder where "Right_Click_Register_DLL.reg" is located, run this file it will ask if you would like to merge this to the registry, click yes this will add "Register DLL" when you right click on a DLL to register which is our next step
I will suggest that you extract the vs910.dll on your desktop and from there Right Click on the VS910.DLL and click register it will register and will create to other files .XML dont touch them please so then our dll is registered. (make sure you have followed the guide and installed the components and generic models as stated above PLEASE IMPORTANT)
Reboot your computer
next connect the LG Esteem phone to your computer once the usb is detected and shows up on your notification bar, from the notification bar please chose INTERNET CONNECTION mode. Once you do that open device manager on your computer and under com ports you will see the LG com port (ignore this)
Next open LGPNST which is also located on "C:\LG Electronics\LGNPST\" once you open it and if you have followed the directions closely the lg esteem will show up as unknown device dont worry about that please
From LGPNST click File select DLL browse to your desktop and select VS910.DLL
NEXT Check this picture out please and do as same View image: LGNPST First page VERY IMPORTANT i downloaded and edited it little but it will look like this.
Next the upgrade option will be visible click it and from there go to BIN FILE and you will see a little folder icon click that and it will let you browse where your .TOT file is
Once the dialogue box opens navigate to desktop where you downloaded or copied the MS910ZVB_01.SB_01.P3018.R1003.tot file because it wants a .bin file, you can only open the .TOT file by typing "*.*" inside the file name query and hit enter and you will see the tot file visible if not copy and paste this to the file name query MS910ZVB_01.SB_01.P3018.R1003.tot and hit enter it will be loaded.
Next click upgrade wait for it to finish and your happy Please MAKE SURE THE PHONE IS SAFE AND THE CABLE DOESNT GET UNPLUGGED OR THE PHONE, dont trip on the wire dont jump on it nothing . (also make sure the phone is charged atleast 30% or you will have to wait till it charges this will work gurantee i have done this COUNTLESS times with my Esteem ever since the .TOT was released and also been flashing my KU990
BTW I know its LGNPST not LGPNST sorry gotta work cant fix all the mistake lol
Those who have updated to the latest zvc update for lg esteem, but regrets it and wants root back you can downgrade back to zvb and its confirmed just did it my self right now
Please follow this guide to downgrade http://androidforums.com/lg-esteem/454895-12-3-11-lg-esteem-ms910-firmware-w-instructions.html dont worry about the dll not registering download the vs910.dll put it on your desktop register that one instead open lgpnst put the esteem in internet connection mode so lgpnst detects the phone click file select dll and select the vs910.dll ok then click on the mode that says unknown and the upgrade option will become clickable from there follow on the guide from here http://androidforums.com/lg-esteem/454895-12-3-11-lg-esteem-ms910-firmware-w-instructions.html and then your back to zvb
UPDATE
Ok to start up thanks to user Jackpot08 a lot for posting the .TOT files and LGpnst big thanks to him.
To start off first download this files Multiupload.com - upload your files to multiple file hosting sites! (LGPNST) Free File Hosting, Online Storage & File Upload with FileServe (ESTEEM'S ZVB STOCK TOT or IMAGE)
The drivers can be obtained when you connect the esteem to the computer it will show up as a cd drive in MY COMPUTER
Since MS910.DLL does work anyway i will provide the one that works which is VS910.DLL link Multiupload.com - upload your files to multiple file hosting sites!
After your done downloading all the file extract the "LGPNST.zip" file where it will be easier for you place the MS910ZVB_01.SB_01.P3018.R1003.tot file on your desktop as well
then install..
LGPNST
LGNPSTv1.2_Store_Version.msi
LGNPST_v1.2_Lab_Version.msi
Then navigate to the folder named "Components" and install this "LGNPST_Components_Ver_5_0_12_0.msi"
Next navigate to "GenericModels" folder and from there install "LGNPST_GenericModels_Ver_5_0_10_0.msi"
Next go back to the original folder where "Right_Click_Register_DLL.reg" is located, run this file it will ask if you would like to merge this to the registry, click yes this will add "Register DLL" when you right click on a DLL to register which is our next step
I will suggest that you extract the vs910.dll on your desktop and from there Right Click on the VS910.DLL and click register it will register and will create to other files .XML dont touch them please so then our dll is registered. (make sure you have followed the guide and installed the components and generic models as stated above PLEASE IMPORTANT)
Reboot your computer
next connect the LG Esteem phone to your computer once the usb is detected and shows up on your notification bar, from the notification bar please chose INTERNET CONNECTION mode. Once you do that open device manager on your computer and under com ports you will see the LG com port (ignore this)
Next open LGPNST which is also located on "C:\LG Electronics\LGNPST\" once you open it and if you have followed the directions closely the lg esteem will show up as unknown device dont worry about that please
From LGPNST click File select DLL browse to your desktop and select VS910.DLL
NEXT Check this picture out please and do as same View image: LGNPST First page VERY IMPORTANT i downloaded and edited it little but it will look like this.
Next the upgrade option will be visible click it and from there go to BIN FILE and you will see a little folder icon click that and it will let you browse where your .TOT file is
Once the dialogue box opens navigate to desktop where you downloaded or copied the MS910ZVB_01.SB_01.P3018.R1003.tot file because it wants a .bin file, you can only open the .TOT file by typing "*.*" inside the file name query and hit enter and you will see the tot file visible if not copy and paste this to the file name query MS910ZVB_01.SB_01.P3018.R1003.tot and hit enter it will be loaded.
Next click upgrade wait for it to finish and your happy Please MAKE SURE THE PHONE IS SAFE AND THE CABLE DOESNT GET UNPLUGGED OR THE PHONE, dont trip on the wire dont jump on it nothing . (also make sure the phone is charged atleast 30% or you will have to wait till it charges this will work gurantee i have done this COUNTLESS times with my Esteem ever since the .TOT was released and also been flashing my KU990
BTW I know its LGNPST not LGPNST sorry gotta work cant fix all the mistake lol
Those who have updated to the latest zvc update for lg esteem, but regrets it and wants root back you can downgrade back to zvb and its confirmed just did it my self right now
Please follow this guide to downgrade http://androidforums.com/lg-esteem/454895-12-3-11-lg-esteem-ms910-firmware-w-instructions.html dont worry about the dll not registering download the vs910.dll put it on your desktop register that one instead open lgpnst put the esteem in internet connection mode so lgpnst detects the phone click file select dll and select the vs910.dll ok then click on the mode that says unknown and the upgrade option will become clickable from there follow on the guide from here http://androidforums.com/lg-esteem/454895-12-3-11-lg-esteem-ms910-firmware-w-instructions.html and then your back to zvb