A BIOS Chip is one of the most important part of one’s PC, without it a PC never works.BIOS chip seldom breaks down that’s why a lot of us dont mind its function. The moment you encounter a “BIOS check sum error….” or suspect a hardware incompatibility,then you will start to remember how important BIOS is in a PC system.In such a situation the next you will think to do is to flash(replace the program) your BIOS via a utility provided by your board manufacturer.
What if your BIOS chip is write-protected?
BIOS can be write-protected via the software(by entering cmos setup) or via jumper setting on your board.But some manufacturer(refer to manual) don’t provide jumper setting on their motherboard, so one option left is to write-enable it via CMOS setup,but the last solution mention above is only good if your BIOS setup is still accessible, in cases where you have a “Bootblock situation……” then it is impossible to enter your CMOS setup.
In this case your last option is to write-enable your BIOS chip directly,you have to disable the write-protect pin in order to flash your BIOS chip succesully.So, next thing you must do is to look(search the net) for the pin layout of a particular BIOS chip in order to bypass the write-protect pin.If your BIOS chip is similar to the figure shown above then you may proceed in write-enabling your BIOS.You may short it exactly as what it was shown in the figure,it will be easier to insert a thin wire in between the BIOS and the socket pin if it is socketed.
After putting a thin wire jumper on your BIOS chip you may now proceed in flashing your BIOS and it should flash successfully otherwise you wrongfully jumper your BIOS chip or has some non BIOS related problem of your motherboard.Remove the jumper after successfully flashing your BIOS chip.
Note:
This trick was successfully tested on the BIOS of a XPC Shuttle CPU, it may work on similar BIOS chip as other claim it, but don’t held me responsible in case something worst happen on your motherboard.Its only a last resort solution before replacing a motherboard.If you don’t want to take the risk I suggest that you try to order a BIOS replacement from your motherboard manufacturer or have it repaired to them.


May 11th, 2010 at 8:15 pm
hello i have a Atmel AT49F002NT chip wich i also want to disable the bios lock
but i dont know wich pins i should connect can you help me?
August 10th, 2010 at 10:41 pm
I have the same issue with my Atmel AT49F002NT, the data sheet says this
on page 4.
“BOOT BLOCK PROGRAMMING LOCKOUT OVERRIDE:
The user can override the boot block programming lockout
by taking the RESET pin to 12 volts. By doing this, pro-
tected boot block data can be altered through a chip erase,
sector erase or word programming. When the RESET pin is
brought back to TTL levels the boot block programming
lockout feature is again active. This feature is not available
on the AT49F002N(T).”
SO are we screwed due that pin one on the AT49F002NT is not RESET, instead it is DC see note on page one. I am going to try to send 12VDC to pin one, what can it hurt, the pc don’t boot anyways…lol