BIOS passwords can be add extra layer of security for desktop and laptop computers, and are used to either prevent a user from changing the BIOS settings or to prevent the PC from booting without a password. BIOS passwords can also be a liability if a user forgot their passwords, or if a malicious user changes the password. Sending the unit back to the manufacturer to have the BIOS reset can be expensive and is usually not covered in an a typical warranty. However, there are a few known backdoors and other tricks of the trade that can be used to bypass or reset the BIOS password on most systems.
To enter the BIOS Setup try these keystrokes:
- AMI BIOS: Del key during the POST
- DTK BIOS: Esc key during the POST
- Award BIOS: Ctrl-Alt-Esc
- misc BIOS: Ctrl-Esc
- Phoenix BIOS: Ctrl-Alt-Esc or Ctrl-Alt-S
- IBM PS/2 BIOS: Ctrl-Alt-Ins after Ctrl-Alt-Del
Many BIOS manufacturers have provided backdoor passwords that can be used to access the BIOS setup in the event you have lost your password. These passwords are case sensitive, so you may wish to try a variety of combinations.
WARNING: Some BIOS configurations will lock you out of the system completely if you type in an incorrect password more than 3 times. Read your manufacturers documentation for the BIOS setting before you begin typing in passwords.
Award BIOS backdoor passwords:
|AWARD SW||J262||shift + syxz|
AMI BIOS Backdoor Passwords:
Phoenix BIOS Backdoor Passwords:
Misc. Common Passwords
Other BIOS Passwords by Manufacturer
|VOBIS & IBM||merlin|
Most Toshiba laptops and some desktop systems will bypass the BIOS password if the left shift key is held down during boot
IBM Aptiva BIOS
Press both mouse buttons repeatedly during the boot
Motherboard “Clear CMOS” Jumper or Dipswitch settings
Many motherboards feature a set of jumpers or dipswitches that will clear the CMOS and wipe all of the custom settings including BIOS passwords. The locations of these jumpers / dipswitches will vary depending on the motherboard manufacturer and ideally you should always refer to the motherboard or computer manufacturers documentation. If the documentation is unavailable, the jumpers/dipswitches can sometimes be found along the edge of the motherboard, next to the CMOS battery, or near the processor. Some manufacturers may label the jumper / dipswitch CLEAR – CLEAR CMOS – CLR – CLRPWD – PASSWD – PASSWORD – PWD. On laptop computers, the dipswitches are usually found under the keyboard or within a compartment at the bottom of the laptop.
Please remember to unplug your PC and use a grounding strip before reaching into your PC and touching the motherboard. Once you locate and rest the jumper switches, turn the computer on and check if the password has been cleared. If it has, turn the computer off and return the jumpers or dipswitches to its original position.
Removing the CMOS Battery
The CMOS settings on most systems are buffered by a small battery that is attached to the motherboard. (It looks like a small watch battery). If you unplug the PC and remove the battery for 10-15 minutes, the CMOS may reset itself and the password should be blank. (Along with any other machine specific settings, so be sure you are familiar with manually reconfiguring the BIOS settings before you do this.) Some manufacturers backup the power to the CMOS chipset by using a capacitor, so if your first attempt fails, leave the battery out (with the system unplugged) for at least 24 hours. Some batteries are actually soldered onto the motherboard making this task more difficult. Unsoldering the battery incorrectly may damage your motherboard and other components, so please don’t attempt this if you are inexperienced. Another option may be to remove the CMOS chip from the motherboard for a period of time.
Note: Removing the battery to reset the CMOS will not work for all PC’s, and almost all of the newer laptops store their BIOS passwords in a manner which does not require continuous power, so removing the CMOS battery may not work at all. IBM Thinkpad laptops lock the hard drive as well as the BIOS when the supervisor password is set. If you reset the BIOS password, but cannot reset the hard drive password, you may not be able to access the drive and it will remain locked, even if you place it in a new laptop. IBM Thinkpads have special jumper switches on the motherboard, and these should be used to reset the system.
Use the Debug command
Boot to MS- DOS prompt, run through the below example, this example is perfectly fine to run on any PC Computer running MS-DOS / Windows and will not harm anything.
DEBUG script that will just reset the password only
Type debug and press enter. (ex. A:\>debug )
After typing debug you will get “-” as a prompt ,type these exactly how they are written.
o 70 10
o 71 20
Explanation of code:
DEBUG ; Run DEBUG, “-” will appear on each line then type:
o 70 20 ; Send 70 to address 18
o 71 21 ; Send 71 to address FF
q ; Quit DEBUG
or you can use this alternate DEBUG script that will just reset the the BIOS
MOV AX,0 <ENTER>
MOV AX,CX <ENTER>
OUT 70,AL <ENTER>
MOV AX,0 <ENTER>
OUT 71,AL <ENTER>
INC CX <ENTER>
CMP CX,100 <ENTER>
JB 103 <ENTER>
INT 20 <ENTER>
<ENTER> Note: Nothing is typed on this line
G <ENTER> By pressing G this will execute the above script
Then reboot and you will get a Setup Checksum Error. Go into setup, correct all the incorrect values, time, date…
Alternatively you can use the program WipeCMOS from a boot floppy
Use the Decoding software
CmosPwd by CGSecurity – This is probably the most up to date and popular CMOS decryption tool. CmosPwd decrypts password stored in cmos used to access BIOS SETUP, you can also backup, restore and erase/kill cmos.You will have to be logged in as administrator, run ioperm -i command and then run cmospwd_win.exe
PC CMOS Cleaner – PC CMOS Cleaner is an easy-to-use tool to recover, delete, decode and display the superior passwords stored in BIOS whatever the brand is. It’s an bootable CD that runs on x86 and x86_64 computers. It can display the superior passwords of the BIOS, remove BIOS password(will set the BIOS to default status, need reset date).