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What is the use of bios passwords?
What is the purpose of a BIOS update?
1. A BIOS update can fix inherent errors and defects in the original BIOS, such as improving memory compatibility, adding support for new CPUs, and introducing new options—similar to software updates that fix bugs and add features.
2. Flashing the BIOS means updating the original firmware file, much like a software upgrade. This process typically occurs under DOS, though some modern systems also support Windows-based flashing.
3. In some cases, especially with Vista OEM systems, users may want to add a SLIC (Software Licensing Internal Code) to bypass certain verification processes. Some individuals online provide modified BIOS files that allow this. However, using virtual BIOS methods or unauthorized modifications on OEM motherboards is risky, as these machines often do not provide official BIOS updates.
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**How to Clear BIOS Password and Flash BIOS**
We know there are two types of BIOS passwords: user password and system password. The user password is used when accessing the BIOS settings, while the system password must be entered before the system performs its self-test. When it comes to removing the user password, there are only two known methods so far. First, discharging the CMOS battery. Second, finding the manufacturer's default password. I will discuss both in detail below.
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**Step-by-Step Methods**
**1. The Most Common and Simple Method – Debug Command**
Most computers allow access and modification of CMOS settings through ports 70H and 71H. One of the easiest ways is to clear all CMOS data, restoring it to factory defaults. To do this, you can use the Debug command in DOS. Here’s how:
Start your computer in MS-DOS mode and enter the following commands:
```
c:\dos>debug
-o 70 21
-o 71 20
-q
```
Or alternatively:
```
c:\dos>debug
-o 70 10
-o 70 01
-q
```
Note: The “-†symbol is part of the system prompt, so you don’t need to type it. After rebooting, the user password should be cleared.
**2. The Most Straightforward Way – Discharge Method**
This method involves opening the computer case and locating the CMOS battery. Disconnecting it for a few seconds usually clears the CMOS. Many modern motherboards have a jumper or DIP switch to discharge the CMOS, making the process even easier. If your motherboard doesn’t have one, simply remove the battery and short the pins for about a minute. Some suggest leaving it disconnected for an hour, but most users find a few seconds sufficient.
[Image: What is the use of BIOS passwords?]
**3. Using Software Tools**
There are several software tools available online that can help you clear the CMOS password. Two common examples are:
1. **BOOTSAFE.EXE** (from PCTOOLS 9.0):
Run BOOTSAFE C:/M to back up CMOS and boot data to a floppy disk. Then edit the CMOS.CPS file and restore it using the same tool.
2. **RESCUE.EXE** (from Norton 8.0):
Create a rescue disk and modify the CMOS.DAT file. Use the rescue disk to restore the CMOS data and reset the password.
Another useful tool is **BiosPwds**, which allows you to retrieve the BIOS password by simply clicking "Get Passwords." It displays the BIOS version, date, and any set passwords.
**4. Cracking via Programming (Less Practical)**
Some people attempt to crack the BIOS password using programming techniques. For example, a BASIC script might read from port 70H and 71H to extract the password. However, this method is rarely effective and requires specific hardware and conditions.
**5. Changing Hardware Configuration**
When the system boots, the BIOS checks the hardware configuration against the CMOS settings. If there is a mismatch, the system may automatically enter the Setup utility without prompting for a password. You can take advantage of this by unplugging peripherals like the sound card or disconnecting the floppy drive. Once in Setup, you can reset the CMOS password and save the changes.
By understanding these methods, users can effectively manage BIOS passwords and perform necessary updates or resets. Always ensure you back up important data before attempting any of these steps, as they can potentially affect system stability.