You need a stock FTF that matches your region or a generic one. Do not use an "OEM" only file.

Open the Flashtool directory and launch either Flashtool.exe (32-bit) or Flashtool64.exe (64-bit) as an administrator.

While holding the button, connect the USB cable from the PC to your phone.

Flashtool will take a moment to prepare the files. A pop-up window will eventually appear, prompting you to connect your phone. Power off your Sony G3311 completely. Hold down the button and plug in the USB cable.

A: No. A "lock remove FTF" only removes the screen lock (pattern/PIN). Network or SIM locks are separate security measures. You would need an unlock code from your carrier to remove a network lock.

In the firmware selector, choose the firmware you downloaded.

The best method is prevention. If you've previously registered your device with Sony's "Protection by my Xperia" service, this is the only method that can remove your lock without losing any data. If not, flashing an FTF or using Xperia Companion are your next best bets.

Install the official Sony Flashmode and Fastboot drivers so your PC can recognize the phone in its download state.

You can now unplug your phone. Press and hold the until you feel the device vibrate. Release it and wait for the phone to boot up. The first boot will take significantly longer than usual (sometimes up to 10 minutes) as the system is rebuilding its cache. Once it reaches the setup screen, you will see that the pattern, PIN, or password lock has been completely removed.

Use a tool like XperiFirm (often built into FlashTool) to download the official stock firmware specifically for the Sony Xperia L1 (G3311) . Ensure the model number matches exactly. Step-by-Step Flashing Guide