Fix Samsung Galaxy A05 (SM-A055F) “No Display / Backlight” After Android 15 Update.

1) Symptoms & Quick Understanding

• After the Android 15 OTA, the screen remains black—no backlight, no UI—like it’s off.
• Plugging in the charger plays the usual chime; sometimes vibration feedback is felt. The device is alive.
• Forced reboot (Vol-Down + Power) doesn’t restore the panel.
• PC may detect the phone in normal mode/charging, but the display stays blank.

This behavior usually points to a panel driver / power sequence mismatch that shipped with the new build for your particular panel/region. Reverting to a stable Android 14 build (with the same or higher bootloader BIT) typically brings the display back immediately after flash.

2) Why It Happens After Android 15

Major version jumps introduce kernel, display HAL, and power management changes. On certain batches of A05 (panel vendor variants), the updated driver stack can fail to initialize the backlight chain. Because this is software-level, a clean flash to Android 14 (One UI 6) that matches the device’s BIT usually restores expected behavior. Later, when Samsung pushes a corrected Android 15 build for your region/BIT, you may update again.

3) Requirements (Drivers, Tools, Files)

4) Enter Download Mode With a Black Screen (Blind)

Because nothing shows on the screen, you must rely on timing and “feel”. Follow the steps precisely; technicians often succeed within a few attempts:

5) Check Model / Region / BIT in SamFW

With the device in Download Mode and detected by SamFW:

1. Open SamFW Tool → confirm the Samsung port shows.
2. Go to Info → Download Mode Info.
3. Note exactly:
   • Model: SM-A055F
   • Region/CSC: e.g., INS, XSG, XXV, etc.
   • BIT/Bootloader Rev: e.g., BIT 9 like a055fxxs9, bit 8 like a055fxxs8.

6) Download the Correct Android 14 Firmware

In your browser, search by model and repository (e.g., “A055F firmware”). Pick your exact region/CSC that matches SamFW Info. Then choose an Android 14 (One UI 6) build that matches your BIT. Save the archive to your PC.

For convenience, keep the file on Desktop and verify the filename suffixes (often include build and bootloader digits). If multiple mirrors exist, use the most reliable one. If a download looks unusually small or corrupt, re-download before flashing.

7) Extract BL/AP/CP/CSC With WinRAR

1. Install WinRAR (link above) if you don’t already have it.
2. Right-click the firmware archive → Extract to…
3. You will get five files:
   • BL_*.tar.md5
   • AP_*.tar.md5 (largest file; allow time to load later)
   • CP_*.tar.md5
   • CSC_*.tar.md5
   • HOME_CSC_*.tar.md5
4. Create a new folder (e.g., A055F_A14_BIT9) and move all five files inside for easy selection in SamFW.

8) Flash Using SamFW → Odin Flash

Full Tutorial Video (Youtube)

9) After Flash: First Boot Checks

• First boot can take 5–10 minutes. Do not interrupt.
• Confirm that the backlight/display is now visible on the Setup/Lock screen.
• Go to Settings → About phone → Software information: verify Android 14 and the correct BIT.
• Test brightness slider, auto-brightness, charging animation, and screen timeout.

10) Pro Tips, Do’s & Don’ts

• BIT Matching: Never attempt lower BIT. If you can’t find your BIT in A14, search other region codes that match your model; do not force a mismatch.
• Cable & Ports: Use short, high-quality cables; prefer rear motherboard USB ports.
• Integrity: If AP takes abnormally long to load or SamFW logs MD5 errors, re-download the package.
• No Interruptions: Don’t disconnect during AP write. If flash fails, leave the phone connected, re-enter Download Mode if needed, and retry.
• Drivers: If the COM port drops mid-flash, reinstall drivers and reboot PC.
• HOME_CSC vs CSC: For panel/backlight issues, clean flash with CSC is safer.
• Later Updates: Once Samsung releases a fixed Android 15 build for your region/BIT, you may update again from A14.

11) Frequently Asked Questions

Q1. Why not just re-flash Android 15?

Because the issue started after the Android 15 update, downgrading to a stable Android 14 build (same BIT) is the quickest way to restore the display. You can try Android 15 again once a compatible build appears for your region/BIT.

Q2. My device shows BIT 9 but I only see BIT 8 firmware.

You cannot downgrade BIT. Keep looking for Android 14 packages that carry BIT 9 for your region/CSC. Flashing a lower BIT will fail.

Q3. SamFW detects the port but the flash fails midway.

Use a different cable/USB port, temporarily disable aggressive antivirus, and ensure no other tools (ADB, Kies, Smart Switch) are holding the port. Re-download firmware if integrity is in doubt.

Q4. Can I keep data using HOME_CSC?

You can attempt it, but for display/backlight faults after a major OTA, clean flash (CSC) is strongly recommended.

Q5. Will flashing trip KNOX?

Flashing official, signed stock firmware via Odin typically does not trip KNOX. Avoid custom binaries to keep KNOX intact.

Q6. I cannot enter Download Mode “blind”. Any trick?

Time the vibration/restart cue precisely: hold Power + Vol Up + Vol Down, plug USB, release Power on vibration, then tap Vol Up after ~1–2 seconds. Repeat several times if needed.

Q7. After flashing A14, the screen is still black.

Re-flash using CSC (clean). Verify BIT/region matches. Try another USB port/cable and ensure firmware files aren’t corrupt.

Q8. Does this erase user data?

CSC will wipe data. HOME_CSC tries to keep data but may keep the bug. If the screen is black, backups are typically not possible beforehand.

12) Downloads

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