FIXED: Samsung A05 Black Screen After Android 15 Update (SM-A055F Downgrade Guide)

The Problem: The Android 15 Update Blackout

If you recently updated your Samsung Galaxy A05 (SM-A055F) to Android 15 and were greeted by a black screen, you are not alone. This is a recurring issue for some users. The phone is technically working—you can receive calls, hear charging sounds, and the internal functions are running—but the display remains completely black, making the phone unusable.

After attempting several minor updates and failing to resolve the issue, I determined the root cause is the Android 15 firmware itself. The solution is a firmware downgrade back to a stable version, specifically Android 14, using the correct flashing tools and files.

⚠️ CRITICAL WARNING BEFORE PROCEEDING

This guide involves flashing custom firmware to your device, which carries risks.

This tutorial is strictly intended for mobile repair technicians or individuals with prior experience and knowledge of firmware flashing, bit versions, and using tools like Odin/SamFw Tool.

If you are inexperienced with these procedures, DO NOT attempt this yourself. Take your phone to a trusted, professional technician in your area. Proceed at your own risk.

Step 1: Preparation & Required Tools

Before you begin the downgrade process, you must have the following installed on your Windows PC:

1. USB Drivers

Your PC must be able to properly recognize the Samsung device in Download Mode.

• Samsung USB Drivers: Ensure you have the latest Samsung USB drivers installed.

• Driver Pack (If needed): If you are unsure about drivers, you can read more about a comprehensive driver pack here: All In One USB Driver Pack for Mobile Phone Repair

2. SamFw Tool

We will use the SamFw Tool for flashing, as it simplifies the process and includes Odin functionality.

• Download Link: SamFw Tool Download

• Download and install the tool on your PC.

Step 2: Entering Download Mode (The Tricky Part)

This is the most challenging step because the phone's display is black. You will have to perform this operation blindly or by physically opening the phone.

Option A: The Blind Guess (Software Method)

This method relies on estimating the timing of the key presses.

1. Start with the Phone OFF (or suspected to be OFF): Connect the USB cable to your PC but NOT to the phone yet.

2. Press and Hold: Press and hold the Volume Down key and the Power key simultaneously for approximately 7 seconds. (This should force a restart, which is effectively a power-off for our purposes).

3. Key Sequence for Download Mode: Release the Power key, but immediately press and hold Volume Up and Volume Down together.

4. Connect Cable: While holding Volume Up and Down, connect the USB cable to the phone.

5. Listen for the Sound: After a few seconds, you should hear a USB connection sound from your PC. This indicates success. If you hear the sound, skip to Step 3.

   • Note: This method is difficult due to the blind nature of the operation.

Option B: The Easy Way (Hardware Method)

If Option A fails, this is the most reliable way to guarantee the phone is completely powered off and enters Download Mode easily.

1. Open the Phone: Carefully open the back cover of the phone (this requires skill).

2. Disconnect Battery: Gently disconnect the main battery connector from the motherboard. This ensures the phone is completely powered off.

3. Reconnect Battery: Reconnect the battery connector. The phone is now powered off and ready.

4. Enter Download Mode: Press and hold the Volume Up and Volume Down buttons simultaneously.

5. Connect Cable: While holding the buttons, connect the USB cable to the phone.

6. Release Keys: After 5 seconds, release the Volume Up and Down keys.

7. Success Indicator: You will hear the USB connection sound on your PC, and the SamFw Tool should now show the Samsung USB port connected.

Step 3: Checking Phone Details and Downloading Firmware

Now that the phone is in Download Mode, we need to gather its specific firmware details to download the correct files.

1. Open SamFw Tool.

2. Get Device Info: In the SamFw Tool interface, click the 'Info' button located to the right of the detected Samsung Port. Then, click [Samsung] Download Mode Info.

3. Note the Details: The tool will retrieve your phone's full details, including the current firmware version, country code (CSC), and most importantly, the BIT VERSION (often labeled as 'Binary' or 'SW Rev').

4. Download Firmware: You need to download an Android 14 firmware file for your device.

   • Crucial Rule: The new Android 14 firmware must have the SAME BIT VERSION as the one currently installed on your phone. You can change the Android version (15 to 14), but the binary/bit version must match.

   • Search Google for "Samsung A05 SM-A055F Android 14 firmware [Your CSC]"

   • Popular sites for firmware downloads include SamFw.com, Sammobile, etc.

Step 4: Flashing the Downgrade Firmware

Once your Android 14 firmware file is downloaded, proceed to flash it.

1. Extract the Firmware: Extract the downloaded ZIP file. You will find four main files:

   • BL_...

   • AP_...

   • CP_...

   • CSC_...

2. Open SamFw Flashing Tab:

   • In the SamFw Tool, navigate to the Samsung tab at the top.

   • Click on the Odin Flash sub-tab.

3. Load the Files: You will see slots for BL, AP, CP, and CSC. Click the Open button next to each option and select the corresponding file from your extracted folder:

   • Load the BL file into the BL slot.

   • Load the AP file into the AP slot.

   • Load the CP file into the CP slot.

   • Load the CSC file into the CSC slot (use the standard CSC file, not the HOME_CSC file).

4. Start Flashing: Double-check that all four files are correctly loaded and your phone is still in Download Mode. Click the Flash button.

5. Wait: The process will take approximately 15-20 minutes to complete. DO NOT disconnect the phone during this time.

6. Success: The tool will indicate PASS!, and your phone will automatically reboot.

Conclusion

When your phone finally powers back on, the display light will be back on, and the phone will function normally on the stable Android 14 version.

If you found this guide helpful, please feel free to leave a comment letting me know you were successful! If you encountered any difficulties or need further clarification on a step, please ask in the comments, and I will do my best to assist you.