I just have to say that this is a wonderful and terrible tutorial.
I spent at least 10 hours reading hundred of post, and researching how to fix my bricked P796 Optimus L9. The part that would have saved me hours, would be if in the first post of the tutorial, if someone had said.
"Hey Listen, your phone is probably messed up because of these things called X-Loaders, and U-Loaders. They are what your phone uses to start up. The Fastboot we have included does not include the correct X and U loaders, so make sure you, AT NO POINT, tell the fastboot to write these to your phone, it will make things worse! What you have to do is find the correct X and U loaders for your phone. Do a google search or look around in these forums, they are out there. They are .bin files, and people usually label them p1.bin and p2.bin. p1 references the x loader, and p2 references the u loader.
So, how do you get the correct loaders onto your phone? Well follow the tutorial for the most part, and then what I did was opened a separate CMD, or Command Prompt window. In that command prompt window go to the folder your x and u loader files are in. In my case they were in the C:/fastboot folder. So to get there type cd.. and hit enter, until you get to just C:/ . then type " cd fastboot " you shouuld see it change directory and show C:/fastboot
This fastboot folder was the same folder that my fastboot.exe was located in. It's probably the bin folder if you downloaded the zip filed here with the fastboot files. Notice I said the same folder that my fastboot.exe was located in, not the start.bat file that you want to click on later.
Then type " fastboot flash x-loader p1.bin "
It should say < waiting for device >
This is when I opened up the start.bat, in windows 7 I could just click on it, and it opened. At this point, you are running this separate program really just to get your phone to connect to the computer, so hit whatever number you want. It will wait for you to plug your phone in with the battery NOT in it. After you plug the usb in, you will have a few seconds to put the battery in. I usually did it instantly. You may hear the device manager click on and off a couple times, but don't worry about it. If you installed the driver for your omap device as described earlier, just hang on a second, and in THE OTHER command prompt window open, you should see it start doing something. It's sending the correct x-loader to your phone. After that command prompt window says finished, close the SECOND command prompt window. The one you started with start.bat. At this point in the command prompt window that is still opened type:
fastboot flash u-boot p2.bin
It should say <waiting for device>
Then just follow the directions above again (under the first time I wrote waiting for device).
If all is successful you should be able to get into S/W Mode, and if you can follow the tutorial, use the LG Mobile Support Tool. Don't forget that the lg tool is terrible at staying connected, and you may need to research alternative ways of utilizing the LG Tool. I'm talking about creating your own server to download the files from, but theres more on that if you search these forums.
Now, I didn't even use the LG Mobile Support Tool - what I did was I found an .img file, that was the original recovery image for my phone. If you can find that. You can utilize Fastboot again.
To utilize fastboot and skip the LG Mobile Support Tool:
First find your original recovery image for your phone. For example here is the one for mine the P769 Optimus L9 is called p4_769.img
After you have your image file, you want to copy it into the same folder that your FASTBOOT.EXE is located. Just like we did before, open up CMD, or command prompt. Change directory to where your fastboot.exe file is and type:
fastboot flash recovery p4_769.img
now I'm typing p4_769.img there because that's the name of my recovery file. You would type the name of your img file.
After you type that and hit enter, you should get that <waiting for device> like we saw earlier.
This is when you can run the start.bat (and open a separate command prompt window) in you fastboot folder. After the command prompt window loads hit whatever number you want, it doesn't matter, then it will wait for you to connect your phone to the usb without the battery. As soon as you connect the usb, youre going to want to quickly put the battery in. After you do this, just wait a couple seconds, and in the other command prompt window, you should see that its writing your recovery img file to your phone.
Ok, so now go ahead and unplug your phone, when you power it on, you will likely see a little dead android guy. This is when we can hard reset it, by pressing and holding volume down, home, and then power. Hold those buttons until you see your phone is starting to come up. It should then install everything, just like a brand new phone again.
I hope this was helpful, it would have helped me a lot, and saved me a lot of time. Now, I'm sure that A LOT of people don't need descriptions like this, but I honestly feel like I am very computer savvy, and these tutorials were just complete gibberish to me.