Firmware Samsung G3812B Galaxy S3 Slim

OS: Android 4.2 (Jelly Bean); TouchWiz UI

CPU: Quad-core 1.2 GHz

Display: 4.52" inc

Camera: 5 MP, Single

Before flashing, you need
Create a full backup of the firmware.
The battery must be 100% charged.

1. Flashing your phone using CWM Recovery
2. Flashing the phone using TWRP Recovery
3. Flashing the phone using Fastboot

1. Phone flashing using CWM Recovery
The rich functionality of CWM Recovery www.clockworkmod.com allows you to perform many manipulations with the device, including rolling the firmware. By default, stock Recovery is installed in the devices, which means that first you need to install the ClockWorkMod Recovery utility itself.
The general firmware process described below is for ZIP files. Instructions: - Download the firmware and place it on the phone's SD card.
- Next, turn off your phone.
- Press a certain combination of buttons on the phone, the combination may vary depending on the manufacturer of the phone. If you do not know the required combination, try pressing the following keys.
- Press the buttons: Volume up (or Volume Down) (+Home) + Power together for a while.
- As a result, the smartphone will boot in Recovery mode (engineering recovery menu).
- Use the volume buttons to navigate the menu, and use the Power button to select.
- Then select 'Wipe data / factory reset' from the menu.
- Use the volume buttons to select 'Yes - delete all user data'.
- Next in the menu, select 'Wipe cashe partition'.
- Use the volume buttons to select 'Yes - Wipe cache' .
- From the Recovery mode menu select 'advanced' .
- Use the volume buttons to select 'Wipe Dalvik Cache'.
- Next in the menu, select 'Yes - Wipe Dalvik Cache'.
Go back, press 'Go Back'.
- From the menu select 'mounts and storage' .
- Then select 'format / system' from the menu.
- Next in the menu, select 'Yes - Format' .
Go back, press 'Go Back'.
- Select 'install zip from sdcard' from the menu.
- Then select 'choose zip from sdcard' from the menu.
- Next in the menu, select 'Yes - Install your firmware name' .
- Select 'Reboot system now' with the volume buttons and press the Power button.

2. Flashing the phone using TWRP Recovery
For those who prefer working with the utility in the form of TWRP Recovery, the following instructions for the step-by-step installation of the update in the form of a ZIP archive are offered:
- Upload the file with the firmware image to the phone's SD card.
- Go to TWRP recovery. This is done in the same way as with CWM.
- Perform a factory reset by tapping the 'Wipe' option in the main menu. When finished cleaning the phone, return to the original menu by pressing the 'Back' key.
- In the main menu, select 'Install' and find the previously downloaded firmware image. Click on it by dragging the slider to the side.
- The process of flashing the phone will take 2-3 minutes.
- Upon completion, the utility will automatically display a message about successful flashing. By clicking on the item 'Reboot System', reboot the device.

3. Flashing the phone using Fastboot
A universal tool for flashing Android smartphones using a PC is the Fastboot utility. It is part of the SDK Platform Tools, which means it is suitable for a large number of devices.
Before starting the firmware, you need to get access to the system kernel. Very often, many manufacturers block this system parameter, not wanting users to change the system files of their firmware images with their own hands. To do this, you need to unblock Bootloader. To do this, you need to study the detailed instructions for configuring and managing the command line. Before starting the firmware using a computer, do not forget to enable USB debugging of the device in the engineering settings of the device.
- Copy the .zip archive with the image, and place it in the folder with 'ADB'
- Put your smartphone in fastboot mode and write the prompt in the command line: fastbooflash zip filename.zip, where filename.zip is the name of your firmware.
- Wait for the end of the installation and reboot your phone.

Thomas Nilan
Smartphone Expert

Thomas Nilan is a mobile phone expert with in-depth knowledge of the Android and iOS operating systems, who understands the settings of various hidden features that allow you to expand the capabilities of your smartphone, as well as get information about what is going on inside the phone for future repairs. He is an authority in his field, which has allowed him to become a ghostwriter for several technology publications, and he enjoys writing small mobile applications for testing smartphones.