[LG Optimus 2x] x_justin:
All credits of this solution go to user dcseek who brought us the solution for this incredible annoying bug on our phones. It's not a bug actually. I think we should blame ourselfs, because it went all wrong when flashing a baseband. Personally I think it goes wrong when flashing a baseband fails and you have to try it again (yup, smartflash) or when flashing a korean baseband.

I decided to make a thread in the Q&A section, BUT BE CAREFUL!!! this is serious business, but concerning how many noobs are facing this bug (like me), it's worth to fix it.

Before you continue, all data will be wiped! Make sure to backup anything you need!!! Including Internal SD!!!

I am NOT responsible for any damage you possible create. I don't think you can brick your phone because our phone seems to be unbrickable, but I do not want to be blamed for any damage. I just made a guide on which I spent some of my free time to make it easier. I saw a lot of questions regarding hyperterminal. All I can say is: it's quiet easy!

Q: What's the problem?

A: Data connection won't be established after let's say beïng 20 minutes or more on wifi. Airplane on/off or rebooting is the only way to fix... There are also other problems related tot this fix. No guarantee, but connection losses etc. can be fixed with this!

Q: What causes this problem?

Two possible reasons, both are beïng fixed with this procedure:

A1) imei is totally lost or reset to something like 356200000000000 Check your imei by calling *#06#

A2) Some old calibration data in the radio will cause an unknown network state, which is actually edge (the fastest GSM connection). Old radio calibration data needs to be cleared.

Q: Are there other concequences?

A1: Yes, edge won't work, so everytime edge is requested, you will get a signal drop. I'm not sure but it seems like signal loss is caused by this

A2: 3g battery drain! Radio is sending a lot of data to the provider, I logged it and I saw many old useless data passing.

How do you do it?

First you will need a stock based rom. I recommend Stefan's unbrick rom, because you can flash it over every setup. You don't have to think about what you have right now, wether you've ICS, GB, CM, Stock, it doesn't matter. It's also a very easy one-click installation.

Download here It's a customized stock rom with a lot of nice upgrades and features, but the most important thing for this tutorial is to have a rom which everyone can flash with a few clicks and also contains the hidden menu from LG.

How to install?

Unpack rom

- Unpack Stefan's 7z file with 7zip or your favourite unzipper.

- 7zip is free, click

Prepare Phone

-Power down phone

-Remove battery

-Hold VOL_DWN+VOL_UP & plug in USB connection from computer (note, your phone will not visibly respond but it will boot to APX mode quickly)

-Open Device Manager in Windows and you should see "APX Device" listed with an error, or not if you have used NVFlash before

-Right click on the APX device

-Select 'Update driver software'

-Select 'Browse my computer...'

-Select 'Let me pick...'

-Select 'Have disk'

-Browse to directory you extracted the *driver* software to above (It's included in Stefan's zip)

-Select 'NVIDIA USB Boot-recovery driver for mobile devices'

-Accept any warnings, including the big red alert (you may need to disable UAC)

-Now in Device Manager under 'USB Controllers' you should have an 'NVIDIA USB Boot-recovery driver for mobile devices'

If not, uninstall the driver, reboot, rinse and repeat

Install the rom:

- Go to the folder where you unpacked Stefans rom

- Run Windows installer and follow instructions on screen, should be peace of cake for everyone!

- DONE :)

Now you've got a stock rom, it's time to flash your favorite baseband. Thanks to TonyP, there is a special topic about basebands. Please do not discuss here which one to choose.

TonyP's baseband tread

Flash it like normal, except for checking Erase CAL data. This time you have to enable the checkbox:

If you get an error near the end, please see TonyP's topic how to solve! Or try 10 times like me, then it works too.

Congratulations! If your imei wasn't lost yet, it is now:) Now we have to restore it.

Step one - download Hyperterminal:

Download free trial, works perfectly on win7 x64 and more: click

Step two - connect phone in the right way

Boot the stock rom, you can cancel setup wizzards if you want. It's not important. Go to phone and call 1809#*990# when you have an old stock rom and call 3845#*990# when you have an ICS stock rom. Thats the hidden menu. Go to port settings and select CP USB (which is Com Port USB). Just click OK without clicking the checkbox to set it on boot. Connect USB cable and wait for your PC to install the drivers.

If all goes well, go to device manager (right click computer > properties > device manager somewere over there)

Note that in my case, it's com6. In your case it could be different. Write down which com port says LGE mobile USB serial port.

Step three - configure the program:

It's easy. Start as admin. Just cancel all the phone and location setup's until you get a blank terminal screen.

Click cancel in this window:

Then click yes to continue cancelling in the popup. Then the following window will appear. Click cancel too:

Now you should see a blank window. Click in it somewhere. A new window appears where you can choose the right com port. Choose the right one, which we got from the previous step. Note that it's probably just 'com x' and NOT LGE xxx xxx (that one sounds more logic but that's another port).

Click properties and select the right options like these:

Click ok twice and you if you did it right, you see this window with the state 'connected' in the lower left corner:

Type 'AT' (without the quotes) and hit enter. Wait for response. If response is 'OK' then you did a good job! Continue to the next step. If you don't see OK try another com port until you see OK.

Now I don't have any screenshots left. But now it's peace of cake.

Type: at%imei [hit enter]

Result is your current imei. You can check it.

Now, you have to write your own imei back with the following command (imei is on a sticker under the battery):

Originally Posted by Raum1807

You should add that the IMEI number must be entered without dashes. It seems to be a common mistake.

For example if your IMEI on the sticker is 123456-78-901234-5 then the command must be at%imei=123456789012345

Just type that, like 'at%imei=123456789012345' (without quotes) and hit enter. You should get a message that your imei is written with succes. Close hyperterminal and reboot your phone.

Check your imei by calling *#06#

It should be the whole number without stripes and dashes.

After this procedure, just flash your own favourite rom back. You can do this as many times as you want. Don't be affraid to damage anything, allthough this procedure is at your own risk.