How to burn a BIOS

Burning a BIOS isn’t as hard as it sounds. Here’s how to burn a BIOS and what to use to do it.

how to burn a bios
You can use a cheap TL866II USB programmer to burn a BIOS onto cheap and readily available EPROMs.

I use a TL 866 2+. Load the software from the manufacturer, because it doesn’t come with the software. Here’s the link I use, as the OEM site is frequently unreachable.

Install the software. I did run it through Virustotal first because it looked sketchy and has been problematic in the past. No problems, but I do wish they had shipped it with software or at least provided a link.

Burning your BIOS chip

If you want to be safe, put a sticker over the window on your chip to prevent accidental erasure. Normally if you don’t have light of very specific wavelengths, it takes so long to erase you don’t need to worry much about it. But it isn’t much effort to put a piece of tape over the window. Any non-transparent, non-translucent tape will do. If you want to be professional looking, you can even print a label on a self-adhesive mailing label and use that. This is convenient because then you also know what is on the chip.

Insert your chip. Pay attention to the orientation. There is a legend molded into the device showing you which way is up. The chip goes all the way forward in the socket next to the lever.

Verifying your chip

Choose your chip from the menu labeled Select IC. The make and model does make a difference. I ordered National Semiconductor 27c256 chips, but I had to check my invoice. It’s printed on the chips but not well. And chips can be remarked. Fortunately, there’s functionality to double check all that.

Next go to device, and click blank check. This verifies that the chip is actually blank, and it also verifies the chip is what it says it is. This is important. Two chips with the same number from different manufacturers can be different from a programming standpoint. They’re interchangeable once programmed, but may need different voltages. So, if my chips are actually relabeled chips made by someone else, they may not program right. So this step can save you some ruined chips.

Programming the chip

Load your image file. Go to file, and pick open, then choose your image file. You will need to know if your file is raw binary format or Intel hex. Choose the correct option from the next menu. Other than that you can usually use the defaults.

Then click the program button. It’s an icon that looks like a chip with the letter p on it, and it’s red.

The programmer has an activity light like a disk drive or a USB stick. Since there is not a lot of data to write, it goes pretty quick. You can watch the progress on your screen, but don’t expect it to take very long.

Hit cancel when you are finished. I know it doesn’t seem like that’s what you should click, but your chip is programmed, so you don’t break anything by clicking cancel.

If you want, click tools, then pick verify. This will verify the image on the chip matches what you loaded into the program’s buffer.

Now you can remove the chip, and if the BIOS is the type that requires a second chip, repeat for the image for the other chip.

Using your freshly burned chips

When you’re done, set the chip with the legs on a table and then tilt the chip up to a 90 degree angle. Then do the other side. This is called rolling a chip. Now you can plug the chips into the appropriate socket on your motherboard. Here’s the chip puller I recommend.

Getting BIOS images

I can’t really tell you where to get your images, because it’s going to vary based on your machine. I assume if you want to know how to burn a BIOS to a chip, you probably have an image already or know where to get the image you want. The exception being XT to IDE.

Hopefully you also know the capacity you need. I know for the images I needed to burn, they are supposed to be 27c256 chips. The files are 32K in size, and 32 kB is 256 kilobits. So generally speaking, take the size of your file, multiply it by 8, and that is the number you want to look for on your chip. You usually can go bigger, but if you do, you will need to pad the file to fit. If I were going to write a 256-kilobit image on a 27c512, I would use the command copy /b filename + filename filename512 from a command prompt and then I would write filename512 to my chips.

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