How To Reset Bios Password Hp Elitebook 840 G3 -

Title: How To Reset BIOS Password on HP EliteBook 840 G3 (Master Guide)

Posted by: TechSolutions

If you have a forgotten BIOS Administrator password on your HP EliteBook 840 G3, you are essentially locked out of changing boot order, hardware settings, or even booting from a USB drive. Unlike desktop PCs, you cannot simply remove the CMOS battery to clear this.

Here are the three working methods to reset it, ranging from easiest to most technical. How To Reset Bios Password Hp Elitebook 840 G3

5. Method 3: HP Master Password (Via HP Support)

If hardware method fails:

  1. Boot the laptop and press F10 to enter BIOS.
  2. On the password prompt, press Ctrl + Enter or type any wrong password 3 times until you see a “System Disabled” code (e.g., 95738462).
  3. Call HP Support or use HP Password Reset Tool (for authorized service centers).
  4. Provide the code and proof of ownership to receive a master unlock password.

Step-by-Step Instructions:

  1. Recreate the Lock Screen: Turn on the laptop. When the BIOS password prompt appears, press Enter or type a random password three times (e.g., 1234, wrong, test).
  2. Record the Code: After three failures, the screen will change. On the HP EliteBook 840 G3, you will see one of two things:
    • System Disable Code: A numeric string (e.g., 85823419).
    • System Number: A combination of letters and numbers, often starting with CNU or SN followed by 10-15 characters (e.g., CNU1234ABC).
  3. Generate the Master Password:
    • On a different computer or phone (not the locked laptop), go to bios-pw.org (a reputable repository of manufacturer master key algorithms).
    • Enter your "System Disable Code" or the numeric part of your "System Number."
    • The site will generate 3-5 possible passwords (usually labeled Ctrl+S, Ctrl+Enter, etc.).
  4. Input the Code:
    • Return to the locked HP EliteBook 840 G3.
    • Type the first suggested password carefully. BIOS passwords are case-sensitive.
    • If it fails, try the next one. Use the function keys (Ctrl, Alt, Shift) as described on the website.

Note: This method works on approximately 70% of EliteBook 840 G3 models manufactured before mid-2019. Newer firmware updates may patch this backdoor.

Method 3: Short the SMC/BIOS Chip (Advanced - Laptop open)

This is a physical jumper method for the 840 G3 specifically. Title: How To Reset BIOS Password on HP

  1. With the bottom cover off (from Method 2), locate the BIOS Security Chip (usually near the RAM slots).
  2. Look for two small circular pads labeled "JBIOS_BAT" or two pins near the CMOS battery connector.
  3. Use a metal paperclip or tweezers to short (touch) these two points together.
  4. While holding the short, plug in the AC power adapter (do not turn it on).
  5. Count to 10, then remove the short.
  6. Reboot the laptop. The password should be cleared.

The Process:

  1. Locate the BIOS Chip: Disassemble the HP EliteBook 840 G3 (remove battery, bottom cover, motherboard). Look for an 8-pin chip labeled Winbond 25Q64FWSIG or MX25L6473E. It is usually near the SATA hard drive connector or under a thermal pad.
  2. Connect the Programmer:
    • Attach the SOIC8 clip to the chip. Ensure pin 1 (marked by a dot or indentation on the chip) aligns with pin 1 on the clip (red wire on CH341A).
    • Connect the clip to the CH341A programmer.
    • Plug the CH341A into your USB port on a working PC.
  3. Read the Dump: Open AsProgrammer. Detect the chip. Click Read. This creates a .bin file of your current BIOS (including the password hash).
  4. Find the Password Offset: This is the tricky part. Using a hex editor (like HxD), search for the string HPQOEM or SVP (Setup Verification Password). The password hash is stored in non-standard locations. For the 840 G3, look near offset 0x2000 or 0x21000.
  5. Zero Out the Password: Replace the hex values in the password region with FF or 00. Alternatively, find a clean BIOS dump online for the exact same motherboard model (VERY risky—can brick the laptop).
  6. Write Back: Click Erase, then Write, then Verify the new BIOS file.
  7. Reassemble: Remove the programmer, reassemble the laptop. The password will be gone.

Warning: One wrong click can turn your EliteBook into a $200 paperweight. Do not attempt this unless you have experience with SPI flashing.

Data to Pre-fill in Support Requests

Method 2: The Hardware Hack (The Solder Jump)

This is where the report gets interesting. The 840 G3 stores the BIOS password on a Microchip 25Q64FWSIG (an 8-pin SPI flash chip) located on the motherboard. This chip holds the system firmware (BIOS) and the NVRAM region where the password hash lives.

To reset it, you have two hardware paths: Boot the laptop and press F10 to enter BIOS

B. The Programmer Method (The Real Solution)

This is the industry standard for repair shops.

Tools needed:

Steps:

  1. Disassemble the 840 G3 completely. The BIOS chip is near the RAM slots, under a small sticker.
  2. Attach the SOIC-8 clip to the 25Q64FWSIG chip (pin 1 alignment is critical).
  3. Connect the clip to the CH341A programmer, then to a USB port on a working PC.
  4. Use software like AsProgrammer or FlashROM to read the current BIOS (backup first!).
  5. Download a clean, password-free BIOS dump for the 840 G3 from a repository like Badcaps.net.
  6. Flash the clean BIOS over the existing one.
  7. Reassemble.

Result: 100% success. The password is gone. However, you also lose the device’s serial number and Windows license key stored in the BIOS (Microsoft usually re-activates automatically).

Назад
Сверху