[LG Thrill 4G] oldhouseye:
Don't have to go 21A anymore!!!

Owning this thing for a few months now. Had been on rooted stock Froyo until the day before yesterday. I finally got tired charging it 3 times a day. I had bought some cheap spare batteries from e-bay. They claim to have 1986mah but they don't last as long as the stock 1500 mah one. But, I told myself, but I have 2 spares (3 in total counting the stock one), how bad could it be? Guess what, it is bad. Basically, if the battery is not at 70% at middle night, then it surely will be drained before 7:15 AM in the morning (my alarm is set to 7:15 AM). After a few late for work, I decided that I had enough.

I've been following this thread for awhile. Now I decided to do it. So I downloaded all the necessary files and here was how it went: (if you want to do the same, just follow the instruction in the first post of this thread, it's great! When you hit a wall, check the following to see if my experience is helpful, good luck!)

[I did all these on Windows 7]

1. Installing "B2CAppSetup.exe" and "USB Driver", and you don't see anything happening after clicked "Install USB Driver" button (this is because your phone is connected), or you can't find "P920" in the phone list:

Don't click "install USB Driver", use Menu bar: "Customer Support" -> "Application, Manual & USB Driver Download...", then search for your IMEI or S/N, file is saved to "c:\LGP925". This is the driver that works when phone is in "Download Mode".

At first, I installed a USB driver I found directly through LG's web site. File name is "LGAndroidDriver_Ver_1.0_All.exe". The driver works if the phone is powered up.

2. Flashing 20A, and you see "Scheduled Server Maintenance ...... LGMobile Phone software upgrade service will be temporarily unavailable"

Follow:

How to prevent LG Mobile Support Tool update - thanks to unknown_world

3. Flashing 20A, and you don't see the "Clear Phone Software update Registry / Country / Language" popup

Same as 2. Make sure "Small HTTP" is running, required files are in "c:/shttps/www", and "hosts" file is modified and saved.

4. Flashing 20A, and you stuck at about 6% at the last stage of upgrade, then get "communication error".

Watch the video in the instruction post to learn how to put your phone in "Download Mode". NOTE!!! you need to have the driver for the download mode, read 1.!

5. Phone is in Download Mode, but the "LG Mobile USB Modem" device in the "Device Manager" is an unknown device and Windows 7 could not find driver to it.

If you have done 1, this should not happen.

6. Finished flashing 20A, but failed flashing 21A

For some reason, I couldn't flash 21A. But 20A is not rootable, or should I say, was! Today there's a new post, 20X is finally rooted! Dig in from here. Thanks to darkoctavius for forwarding and Dan rossenberg for saving us!

7. Rooted 20A, now the 4G (or 3G) connection

My network shows 3G with an H. But I can't connect to the mobile network. Follow these on the phone:

Settings -> Wireless & networks -> Mobile Networks -> enable Data Enabled -> Access Point Names -> menu button -> New APN -> put in values from bendbowden's post at here.

Haven't test the network speed yet. But basically, the phone is now usable. I love the battery life!!!