Ever since I got my computer with Win 7 Pro in Dec 09, I've been faithfully
backing up and making system images with the built-in Backup and Restore
feature. When I got my laptop it had BIOS version A04 installed by the factory.
I've since upgraded to version A08 based on a recommendation by the built-in
Dell diagnostics utility. On the Dell support website (drivers and downloads)
version A08 is the only listed BIOS for the Vostro 1520.
If I understand things correctly (not always the case!) the BIOS resides as
flash software within the CPU which is on the motherboard. It's the BIOS that
kick-starts the operating system. If the BIOS becomes corrupted or fails, your
computer becomes a paperweight. During a backup, system image, or creating a
restore point, only the hard drive is copied. The BIOS is NOT included. I can
verify this if I use the Dell Recovery Manager and return my computer to
factory settings or use one of my earlier system images. All of the junkware
returns, but the BIOS still shows as A08 at startup.
When a person updates his/her BIOS, will it be backwards compatible? In
other words, if a computer experiences issues and the BIOS is updated as part
of the corrective action, and then the computer has to be returned to it's
original factory state, or to an earlier system image, will the newest BIOS
always be compatible? If there's a chance the BIOS will not be compatible how
does one make a backup of the earlier BIOS(es) if they're no longer supported
or available at the Dell website?
You have a very good understanding of what a BIOS is, where it lives and how
it's not backed up. In fact, I feel like you've written half my article for me. 
But you also raise a very important question about backwards compatibility.
I'll address that, and clarify a couple of the items you mention.
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“Flashing the BIOS” is not really all that difficult. These days, manufacturers offer BIOS updates as a download, and they come with very specific instructions. I’ve done a few BIOS updates, and have only ever run in to problems on one occasion. The computer gave a specific warning that I was about to install an incorrect BIOS update, and that I had best stop. I did. Disaster averted. If your BIOS ever became corrupted, you’d have little trouble getting the correct update on to a flash drive, and resolving the issue by following the instructions provided.
The article was very informative. I always thought that when you did a complete backup that the BIOS was included in the backup.
Although bad bios flashes are much more rare than they used to be, they can still occur. One thing you should never attempt, to fix a poor running computer, by flashing your bios. If your system isn’t stable, that is when you will likely experience a bios flash gone bad. especially with a Windows based flashing tool. which is what most manufacturers offer these days, and if your bios flash has left your system un bootable, the Windows based flashing tool will not work obviously. If you read some help forums, you will see a lot of people still having problems, usually because they didn’t know what they were doing, and tried to fix stability issues by flashing their bios.
I’d like to add a quick comment about backup. One of the first things I do with any new system is to create a folder on drive C called “Upgrades”. Then whenever I download software, drivers or in the case of this example, a BIOS Flash Utility, it too will have a folder under “Upgrades”. If a downloaded software product has a license key, I put a word document in the folder with the key and date of expiration. This whole folder (“Upgrades”) is part of my backup scheme. It keeps me well organized and I no longer lose this important information.
There are always older versions available on the Dell website for BIOS and other driver updates, that are posted. For the Vostro 1520, you can check the link below:
http://tinyurl.com/vos1520
These are the older versions of the BIOS for your model. However, it is not ‘recommended’ to downgrade the BIOS unless it is specifically suggested or if you are facing serious issues after updating the BIOS.
Dear Leo,
Just a couple of important points that were missed. If you do not have a battery backup for your computer and there is a power failure or surge during the flashing process of the BIOS, the motherboard can be rendered completely useless. I do not recommend flashing the BIOS of any device unless there is a valid reason for doing it. If nothing is wrong, don’t fix it just because there is a newer version.
Also, there is a difference between the CMOS and the BIOS although the terms are often used interchangeably. The BIOS on the motherboard contains the instructions on how the computer boots and is only modified or updated with BIOS updates (as in flashing the BIOS), the CMOS is powered by the CMOS battery and contains your system settings and is modified by entering the CMOS Setup. There were tools that could backup the CMOS settings a few years back, but in this day and age of motherboards with reset jumpers, why bother?
I would like to know more about the jumper that restores the BIOS. The only jumper I am aware of simply restores the CMOS setting. If your BIOS firmware is blown away, there is no fixing that without a BIOS chip transplant, or replacement of the motherboard.
Feel free to write me to discuss the topic…I have a few horror stories to share. –Sandy Coulter
@Sandy
Yes, the majority of computers nowadays only reset the CMOS, which does nothing if a flash has gone wrong, although if you accidentally set a setting wrong resetting the CMOS will fix it (although the only setting I can really think of that would do this would be the clocks, and most of the motherboards used by OEM’s won’t allow you to fiddle these anyway)
Many enthusiast motherboards nowadays, however, have dual BIOS’s, so if the flash goes wrong it will not brick the computer, and others will automatically flash from a flash drive even if the BIOS is broken, but such tech generally does not filter down to the ‘average’ user. The only reason I have had to flash my BIOS is to allow Win7 to run (it was unstable before).
Leo,
I have always known the term CMOS to be an abbreviation for “Complementary Metal Oxide Semiconductor”
Which is the material that the Early BIOS Integrated Circuit (IC) chips were made of.
The XP box I am using now shows the title “Phoenix Award BIOS CMOS” when I go to the BIOS Setup on it.
This BIOS can be upgraded by Flashing it.
I don’t know if these current Flash BIOS chips are made of the same CMOS substance or not.
The older BIOS’s couldn’t be Flashed.
I think way back then You would have to unplug the older BIOS IC from its socket and replace it with an newer, updated version of the BIOS.
That is, if the BIOS chip wasn’t soldered onto the Motherboard.
I’ve never upgraded the BIOS on my old 1994 486 computer.
The Battery on it has died so I just set the Date and Time when ever I turn that box on so I can use it. ;-)
If you think of the CMOS as a Hard Drive, and the BIOS as a Software Program, you’ll always understand the fine distinction betwen the two.
Hello, I am wondering if a bios that is live update will get rid of a virus in my bios… I have zeroed out the drives but I cannot get rid of the boot sector write virus. Do I need to flash the bios or will a liveupdate bios fix itself? This is my school and personal pc and it has got to be fixed like yesterday, please if you can help me let me know. I have tried all I usually have to but I cant get this one to go away and there is no bios flash for my MSI motherboard only live update…the motherboard is rs482m4… Thank you.
18-Jul-2010
How exactly is a bios refalashed 9with a clean copy)?
28-Oct-2010
sorry for the typo, I mean how do we reflash BIOS?
Your articles show SOME level of technical competence, and an ability to explain things in plain English, but you’re no guru (and neither am I, and I can still tell).
1. Your article about the lack of security of BIOS passwords failed to note that one can take the CMOS battery out and wait for any capacitors to discharge.
2. There are certainly situations where a BIOS backup/restore would be handy. Imagine a laptop which gets a BIOS update that changes the language from English to, say, Japanese. An English speaker who doesn’t read Japanese would want to restore it, probably. Access to the motherboard would be problematic.
And that’s from reading just 2 articles.