Showing posts with label BIOS. Show all posts
Showing posts with label BIOS. Show all posts

Boot Block Recovery

AWARD Bootblock recovery:

That shorting trick should work if the boot block code is not corrupted, and it should not be if /sb switch is used when flashing the bios (instead of /wb switch).

The 2 pins to short to force a checksum error varies from chip to chip. But these are usually the highest-numbered address pins (A10 and above).

These are the pins used by the system to read the System BIOS (original.bin for award v6), calculate the ROM checksum and see if it's valid before decompressing it into memory, and subsequently allow Bootblock POST to pass control over to the System BIOS.

You just have to fool the system into believing that the System BIOS is corrupt. This you do by giving your system a hard time reading the System BIOS by shorting the 2 high address pins. And when it could not read the System BIOS properly, ROM Checksum Error is detected "so to speak" and Bootblock recovery is activated.

Sometimes, any combination of the high address pins won't work to force a checksum error in some chips, like my Winbond W49F002U. But shorting the #WE pin with the highest-numbered address pin (A17) worked for this chip. You just have to be experimentative if you're not comfortable with "hot flashing" or "replacement BIOS".

But to avoid further damage to your chip if you're not sure which are the correct pins to short, measure the potential between the 2 pins by a voltmeter while the system is on. If the voltage reading is zero (or no potential at all), it is safe to short these pins.

But do not short the pins while the system is on. Instead, power down then do the short, then power up while still shorting. And as soon as you hear 3 beeps (1 long, 2 short), remove the short at once so that automatic reflashing from Drive A can proceed without errors (assuming you had autoexec.bat in it).

About how to do the shorting, the tip of a screwdriver would do. But with such minute pins on the PLCC chip, I'm pretty comfortable doing it with the tip of my multi-tester or voltmeter probe. Short the pins at the point where they come out of the chip.


AMIBIOS Recovery boot block:
1. Copy a known working BIOS image for your board to a floppy and rename it to AMIBOOT.ROM.
2. Insert the floppy in your system's floppydrive.
3. Power on the system while holding CTRL+Home keys. Release the keys when you hear a beep and/or see the floppy light coming on.
4 . Just wait until you hear 4 beeps. When 4 beeps are heard the reprogramming of the System Block BIOS went succesfull, so then you may restart your system.

Some alternative keys that can be used to force BIOS update (only the System Block will be updated so it's quite safe):
CTRL+Home= restore missing code into system block and clear CMOS when programming went ok.
CTRL+Page Up= restore missing code into system block and clear CMOS or DMI when programming went ok.
CTRL+Page Down= restore missing code into system block and do not clear CMOS and DMI area when programming went ok
Btw: the alternative keys work only with AMIBIOS 7 or higher (so for example an AMI 6.26 BIOS can be only recovered by using CTRL+Home keys).
Boot Block Recovery for FREE

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BLACKOUT Flashing
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Recovering a Corrupt AMI BIOS chip
With motherboards that use BOOT BLOCK BIOS it is possible to recover a corrupted BIOS because the BOOT BLOCK section of the BIOS, which is responsible for booting the computer remains unmodified. When an AMI BIOS becomes corrupt the system will appear to start, but nothing will appear on the screen, the floppy drive light will come on and the system will access the floppy drive repeatedly. If your motherboard has an ISA slot and you have an old ISA video card lying around, put the ISA video card in your system and connect the monitor. The BOOT BLOCK section of the BIOS only supports ISA video cards, so if you do not have an ISA video card or your motherboard does not have ISA slots, you will have to restore your BIOS blind, with no monitor to show you what’s going on.

AMI has integrated a recovery routine into the BOOT BLOCK of the BIOS, which in the event the BIOS becomes corrupt can be used to restore the BIOS to a working state. The routine is called when the SYSTEM BLOCK of the BIOS is empty. The restore routine will access the floppy drive looking for a BIOS file names AMIBOOT.ROM, this is why the floppy drive light comes on and the drive spins. If the file is found it is loaded into the SYSTEM BLOCK of the BIOS to replace the missing information. To restore your BIOS simply copy a working BIOS file to a floppy diskette and rename it AMIBOOT.ROM, then insert it into the computer while the power is on. The diskette does not need to be bootable or contain a flash utility. After about four minutes the system will beep four times. Remove the floppy diskette from the drive and reboot the computer. The BIOS should now be restored.

Recovering a Corrupt AWARD BIOS
With AWARD BIOS the process is similar but still a bit different. To recover an AWARD BIOS you will need to create a floppy diskette with a working BIOS file in .BIN format, an AWARD flash utility and an AUTOEXEC.BAT file. AWARD BIOS will not automatically restore the BIOS information to the SYSTEM BLOCK for this reason you will need to add the commands necessary to flash the BIOS in the AUTOEXEC.BAT file. The system will run the AUTOEXE.BAT file, which will in turn flash the BIOS. This is fairly easy. Here are the steps you need to take.

· Create a bootable floppy diskette
· Copy the BIOS file and flash utility to the diskette
· Create an text file with any standard text editor and add the following lines

@ECHO OFF
FLASH763 BIOSFILE.BIN /py

In the above example I am assuming that you are using the FLASH763.EXE flash utility. You will need to replace the FLASH763 with the name of whatever flash utility you are using, and replace the BIOSFILE.BIN with the name of the BIOS file you are using. You will also need to change the ‘/py’ to whatever the command is for your flash utility to automatically program the BIOS without user intervention. If you do not know the command to automatically flash your BIOS type the name of the flash utility with a space and then /? to display the utility’s help screen. The help screen should pecify the command switch to automatically flash your BIOS. If you are using the FLASH763.EXE utility then the switch to automatically flash your BIOS is ‘/py’.

How to Bypass BIOS Passwords

BIOS passwords can add an extra layer of security for desktop and laptop computers. They are used to either prevent a user from changing the BIOS settings or to prevent the PC from booting without a password. Unfortunately, BIOS passwords can also be a liability if a user forgets their password, or changes the password to intentionally lock out the corporate IT department. Sending the unit back to the manufacturer to have the BIOS reset can be expensive and is usually not covered in the warranty. Never fear, all is not lost. There are a few known backdoors and other tricks of the trade that can be used to bypass or reset the BIOS

DISCLAIMER
This article is intended for IT Professionals and systems administrators with experience servicing computer hardware. It is not intended for home users, hackers, or computer thieves attempting to crack the password on a stolen PC. Please do not attempt any of these procedures if you are unfamiliar with computer hardware, and please use this information responsibly. LabMice.net is not responsible for the use or misuse of this material, including loss of data, damage to hardware, or personal injury.

Before attempting to bypass the BIOS password on a computer, please take a minute to contact the hardware manufacturer support staff directly and ask for their recommended methods of bypassing the BIOS security. In the event the manufacturer cannot (or will not) help you, there are a number of methods that can be used to bypass or reset the BIOS password yourself. They include:

Using a manufacturers backdoor password to access the BIOS

Use password cracking software

Reset the CMOS using the jumpers or solder beads.

Removing the CMOS battery for at least 10 minutes

Overloading the keyboard buffer

Using a professional service

Please remember that most BIOS passwords do not protect the hard drive, so if you need to recover the data, simply remove the hard drive and install it in an identical system, or configure it as a slave drive in an existing system. The exception to this are laptops, especially IBM Thinkpads, which silently lock the hard drive if the supervisor password is enabled. If the supervisor password is reset without resetting the and hard drive as well, you will be unable to access the data on the drive.

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Backdoor passwords

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. Keep in mind that the key associated to "_" in the US keyboard corresponds to "?" in some European keyboards. Laptops typically have better BIOS security than desktop systems, and we are not aware of any backdoor passwords that will work with name brand laptops.

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:

ALFAROME ALLy aLLy aLLY ALLY aPAf _award AWARD_SW AWARD?SW AWARD SW AWARD PW AWKWARD awkward BIOSTAR CONCAT CONDO Condo d8on djonet HLT J64 J256 J262 j332 j322 KDD Lkwpeter LKWPETER PINT pint SER SKY_FOX SYXZ syxz shift + syxz TTPTHA ZAAADA ZBAAACA ZJAAADC 01322222
589589 589721 595595 598598

AMI BIOS backdoor passwords:

AMI AAAMMMIII BIOS PASSWORD HEWITT RAND AMI?SW AMI_SW LKWPETER A.M.I. CONDO

PHOENIX BIOS backdoor passwords:

phoenix, PHOENIX, CMOS, BIOS

MISC. COMMON PASSWORDS

ALFAROME BIOSTAR biostar biosstar CMOS cmos LKWPETER lkwpeter setup SETUP Syxz Wodj

OTHER BIOS PASSWORDS BY MANUFACTURER

Manufacturer Password
VOBIS & IBM merlin
Dell Dell
Biostar Biostar
Compaq Compaq
Enox xo11nE
Epox central
Freetech Posterie
IWill iwill
Jetway spooml
Packard Bell bell9
QDI QDI
Siemens SKY_FOX
TMC BIGO
Toshiba Toshiba

TOSHIBA BIOS

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

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Password cracking software

The following software can be used to either crack or reset the BIOS on many chipsets. If your PC is locked with a BIOS administrator password that will not allow access to the floppy drive, these utilities may not work. Also, since these utilities do not come from the manufacturer, use them cautiously and at your own risk.

Cmos password recovery tools 3.1
!BIOS (get the how-to article)
RemPass
KILLCMOS

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Using the 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.

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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.

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Overloading the KeyBoard Buffer

On some older computer systems, you can force the CMOS to enter its setup screen on boot by overloading the keyboard buffer. This can be done by booting with the keyboard or mouse unattached to the systems, or on some systems by hitting the ESC key over 100 times in rapid succession.

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Jumping the Solder Beads on the CMOS

It is also possible to reset the CMOS by connecting or "jumping" specific solder beads on the chipset. There are too many chipsets to do a breakdown of which points to jump on individual chipsets, and the location of these solder beads can vary by manufacturer, so please check your computer and motherboard documentation for details. This technique is not recommended for the inexperienced and should be only be used as a "last ditch" effort.

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Using a professional service

If the manufacturer of the laptop or desktop PC can't or won't reset the BIOS password, you still have the option of using a professional service. Password Crackers, Inc., offers a variety of services for desktop and laptop computers for between $100 and $400. For most of these services, you'll need to provide some type of legitimate proof of ownership. This may be difficult if you've acquired the computer second hand or from an online auction.

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