Steps to unlock bootloader on Samsung Galaxy A04

Step 1: Enable The Developer Option and OEM Unlock

To enter the process of unlocking, you are required to enable the developer option first and then OEM unlock.

• Go to settings on your phone.
• Connect Wi-Fi or make your phone connect to the internet.
• Update to latest software version.
• Locate the About Phone - Build number and then tap on it several times until the Developer option get enabled.

• Get back to the main Settings and then tap on Additional Settings->Developer Option.

• In Additional Settings, just tap on OEM Unlocking.
• If the OEM unlocking toggle is missing:
• Make sure that your Samsung Galaxy device is connected to the internet and re-check. The device needs to communicate with Samsung servers for identification.
• Samsung Galaxy A04 devices that are sold in the USA with a Qualcomm Snapdragon SoC come with non-unlockable bootloaders (officially). And so, the OEM unlocking option does not exist on such devices.

Step 2: Unlocking Bootloader on Samsung Galaxy A04

Boot into Download Mode using ADB Commands

• Make sure about the drivers, install properly on the computer. And also, take a backup of the necessary data.
• Connect your Samsung Galaxy A04 to your computer and choose transferring files via USB in your device.
• Launch the Mini ADB & Fastboot (where ADB is installed).

• Issue the following ADB command to ensure that your computer can communicate with your device over ADB:
• adb devices
• Press "Allow" on your device if prompted to Allow USB Debugging.

• Boot Samsung Galaxy A04 into Download mode, type the following command:
• adb reboot download
• After you have done this, your device should show a blue-colored "Warning" screen as shown in the image below.

1. Volume up: Continue
2. Volume up long press: Device unlock mode
3. Volume down: Cancel (restart device)
• Long press and hold the Volume Up key to enter Device Unlock Mode on your device.
• The phone will reboot and erase the data; now disconnect the USB Cable.
• Samsung VaultKeeper will relock the bootloader of your Samsung Galaxy A04 if you factory reset your device.
• Now, wait until the process gets completed and your device is completely rebooted.

Other method

Step 1: Enable The Developer Option and OEM Unlock

To enter the process of unlocking, you are required to enable the developer option first and then USB Debugging and OEM unlock.

• Go to settings on your phone.
• Locate the About Phone - Build number and then tap on it several times until the Developer option get enabled.
• Get back to the main Settings and then tap on Additional Settings (or System) - Developer Option.
• In Additional Settings, just tap on USB Debugging and OEM Unlock.

Step 2: Unlocking Bootloader on Samsung Galaxy A04

• Connect Phone to PC and Verify the connection

• Open the folder where ADB and Fastboot are kept. Open "cmd-here.exe" or open the Command Prompt in the folder by clicking Swift key + right mouse click on an empty space.
• Boot Samsung Galaxy A04 into Fastboot mode, type the following command:

• adb devices
• adb reboot bootloader
• Your phone will boot into bootloader and also you will also see bootloader locked.
• To ensure the drivers are installed properly, type the following command:
• fastboot devices
• fastboot oem get_identifier_token
• You should get an output like Identifier token:
XXXXXXXXXXXXXXXXXXXXXXXX
OKAY [ 0.019s]
finished. total time: 0.019s

• Copy out the Identifier token
• Run this command ; replace XXXXXXXXXXXXXXXXXXXXXXXX with your Identifier token
• ./signidentifier_unlockbootloader.sh XXXXXXXXXXXXXXXXXXXXXXXX signature.bin
• You will now get an output along the following line
Identifier sign script, ver 0.10
1+0 records in
1+0 records out
60 bytes copied, 0.000376481 s, 207 kB/s
Identifier sign successfully

• You should also see a signature.bin file in the modified_fastboot folder
• Finally, run this command
• ./fastboot flashing unlock_bootloader signature.bin
• You should get a prompt on the device asking you to push a volume button to confirm unlock
• The phone will unlock, and all data will be wiped!
• Once you have done, you can reboot your device using the command:
• fastboot reboot
• Finally, you have successfully unlocked the bootloader on the Samsung Galaxy A04.