This Little Chip

Thumbnail: BIOS chip

This tiny chip almost had me without my computer for at least a week.

It stores the BIOS, or Basic Input / Output System, in flash memory on my motherboard. The very first thing that happens when a computer is booted is the decompressing of the BIOS into main memory, which then initializes the computers hardware components, including critical devices such as disk drives and I/O ports. This allows a user to recieve feedback (through video), input commands (through a mouse or keyboard), and install or run operating systems (from a hard drive).

Without a BIOS, none of this would be possible. In the past, motherboard manufacturers have made it a hassle to fool around with the program burned onto the small chip, because improper steps in the reprogramming process could potentially render the chip useless. To update the BIOS, one would have to boot to DOS with a floppy and run a flash program off the disk. Modern motherboards now offer the flexibility to update through special software in Windows, although this process is nowhere near as stable as running through DOS.

Which is something I had to learn the hard way last night.

Recent random rebootings had given me reason to start running the latest BIOS version. Unfortunately, I didn’t have a floppy drive (I opted not to buy one with my new computer because I haven’t used a floppy in years), which meant that I was stuck with the Windows flash software. The software happened to crash at a very early part of the flashing process, which meant that I didn’t even have basic bootup code to get a drive running. At next boot — nothing. No BIOS POST beep, no screen signal, no response from the keyboard. I quickly purchased a floppy drive at the nearest dealer, scrambled to find a disk, put a boot sector on it, but to no avail. There wasn’t even enough code burned onto the chip to get power to the floppy drive.

Normally, when something like this happens, such as the power going out or the floppy being removed during a flash, the BIOS gets corrupted and the chip is dead. The options are to get the motherboard RMA‘d, which means sending the board back to the manufacturer before they send a new one back, or purchasing a new BIOS chip with a good BIOS image on it, which means spending more money and waiting for a replacement. Both choices would take at least a week, if lucky.

Neither option was satisfactory. I couldn’t wait until who-knows-how-long for something to be sent back to me. Being without my computer is like being without my comfort zone, the place where I can listen to music and write, play games to get away, communicate with the rest of the world, or even work on my business with Aaron when I feel so inclined. I looked around the net for a faster solution, and discovered something called hot flashing.

Unfortunately, faster also means riskier. Hot flashing involves swapping two BIOS chips while the computer is running. All that’s needed is a healthy chip, an identical motherboard (which I have at work), a boot disk with appropriate flashing software/image, and naturally, the corrupted chip. A computer is booted to floppy with a good BIOS chip, and after getting to a DOS prompt where a BIOS flash can be performed, the corrupted chip is swapped and re-flashed. As a person who’s already squeamish about running a computer with just a side panel missing (in case water may happen to splash into the case and cause a short, or a foreign object falls in and jams a fan), this was an extremely daunting process. Playing around with chips while a computer is hot means that there’s the risk of electrocution, or short circut that could permanently damage the other components. Theoretically, after the BIOS is finished running, the board stops supplying power to the chip since it’s no longer needed.

I decided to my faith in such a theory. Going on this faith meant that I could pry the chip out with a pair of modified paper clips without having to worry too much about causing a short (special PLCC-socket tongs are available, but rare, and would probably take just as long to arrive after purchase as getting a new board). After a few practice pulls, which, I discovered, loosens the socket and gets progressively easier, I seated the good chip with just enough pressure to make the connections in the socket. After booting successfully, I pried the chip off the board and ran the flash.

The first attempt was unsuccessful, and after trying to boot with a corrupted BIOS, something unexplainable happened. The LED on the motherboard that shows that there’s a connected power supply wouldn’t go out. I pulled the power plug, turned off the ATX switch, undid both the 24-pin EATX and 4-pin 12-volt connectors, and even pulled out the CMOS battery, but the light refused to turn off. My only guess was that the capacitors still had enough energy stored to keep the light on. After resetting the CMOS, and another hot flash attempt, the computer booted with the corrupted chip running the latest BIOS. My Windows installation was fucked (it wouldn’t even boot into safe mode), but after a recovery install, everything was up and running again.

I was down for less than 24 hours.

One comment

  1. good to hear it worked fine. flashing the BIOS is a daunting task. i flashed mine via DOS a few years ago and was lucky enough to get it to work fine the first time. i doubt i’d try hot flashing.. sounds too risky

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