How To Install Custom Recovery

To install a Custom Recovery on your phone, you first need to have your phone rooted and the Android SDK installed on your system. For detailed instructions on rooting your phone and installing the Android SDK, read these articles by me first: 

·                     Rooting LG Optimus One P500

·                     How to install the Android SDK / ADB

Now, once you're up and running with a rooted phone and installed the Android SDK, you'll need to download the recovery files. Here are the recovery files:

 
Download 1: Thunderg Recovery
Download 2: flash_image
both the files are uploaded on Mediafire.com (as per your suggestions)
 
Now to use this Custom Recovery, copy these two files and paste in the root of your SD card (root means the directory L:\ where L is the letter for your Phone's USB Storage, in short, don't create a folder and just paste it on your SD card)
 
I'm assuming that you have installed the Android SDK by now as the next step requires it to be installed. Go above and install the Android SDK before continuing.
If you have installed the Android SDK, follow these steps:

1.            Goto Start Menu > Run and type cmd

2.            In the cmd window, type adb. If you've installed it correctly, you'll see a lot of text on the screen. If you get an error message then you have probably not installed the Android SDK properly.

3.            Type adb shell and hit enter

4.            Type su and hit enter

5.            See your phone at this time and touch the "Allow" option which SuperUser shows you

6.            Now the terminal window will have a # sign appended to it. See this screenshot for a better understanding