Is downgrading of BIOS safe? How do you know if down or upgrade of BIOS is successful

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Thread Starter
Jul 19, 2007
Dear All,
I have a question regarding BIOS upgrades as well as downgrades. First, about downgrading BIOS, is it a safe thing to do? If not, then what makes it not safe? I have Dell Inspiron 640M, with the latest BIOS A10. Not happy with this one due to high pitch sounds coming from the top right hand corner of the laptop. It's been suggested that I downgrade only a couple of revisions back, namely, to either A09 or A08. However, Ive been getting conflicting reports about the safety of downgrading from Dell Tech Support. Some say that it's not done at all, others say that as long as it's only to downgrade back to a couple of previous versions, then risks are not as high as going all the way back to a really early version, such as A03 etc. The risks, I'm told, is in the performance of hard disks. Apparently, if you downgrade to a really early version such as A03, then problems will arise, though I'm not sure what the exact problems are. Moreover, there are those who say that there is no procedure for downgrading and that it is never suggested to anyone to downgrade their BIOS. The notion that it becomes riskier as you downgrade back to a really early version of BIOS such as A03 baffles me, because in my case, prior to doing any kind of updating for BIOS on my laptop, I had version A03, and have not had any kind of improvements, enhancements done to my computer whatsoever. in other words, my computer is the same as when I got it last year in terms of hardware. In terms of software, I have not changed my OS of Windows XP home edition with SP2. I only added iTunes, Firefox, Thunderbird, plus software for a corded keyboard. Therefore, the claim that reverting to a really early version of BIOS such as A03 would pose a greater risk than reverting back to A09 or A08 does not make sense, for my computer worked fine with A03, and I have not changed any of my hardware.
My reason for upgrading is because Dell Support software popped up in the bottom right hand corner saying I needed to upgrade my BIOS to A08, so I did that, then discovered after that there was a critical update of A10, which I installed as well and which I have currently.

Another question I have is this: how do you know for sure that an upgrade or downgrade was successful? Although I have yet to do any downgrading, when I updated my BIOS to A08, then to A10, the download for these two files went fine, I did not get any error messages. Even after I flashed the BIOS with A08 and A10, I got a message saying that the update was successful. However, is it possible that even with a message saying that an update was successful, that there may be some glitch and that the BIOS was NOT updated properly? I ask such a question because ever since upgrading to A10, I've been getting a high pitched sound from the top right hand corner of my laptop. The noise is not consistent in a sense that it was always present just after updating to A10, but now, it is only present when I first power the computer on after it's been shut off completely, and when I put into Standby, then come out of it, the noise always disappears.

Thank you for your time and any help you can provide me with.

PS: I would also like to add that, with all the Tech Support I spoke to at Dell (except for one guy), they were all very hesitant, if not down right against downgrading. What makes downgrading so dangerous/risky? As I understand it, upgrading or downgrading BIOS is about erasing the previous version of BIOS and installing another version. If that is the case, then the process for downgrading and upgrading would be the same for flash BIOS would it not? If so, why is upgrading OK to do, but downgrading is something not done, and is considered "forced." Isn't upgrading "forced" as well (this was the term used by one of the technicians at Dell, saying that downgrading is forcing a BIOS).
May 3, 2006
Downgrading a bios is about as safe as upgrading in that you cannot be interrupted or disaster will strike, but it is in essense no better or worse and is done all the time. I never suggest upgrading a bios unless you have specific issues that the bios update corrects. And seldom upgrade to the newest and never a beat so by all means go back top where it ran right.
You can check the bios version usually in the bios, or by using a utility like Belarc or Everest which you can Google or even Sisoft Sandra all of which have free versions. If you don not see the post information, tapping "esc" as you boot up when you see the Dell screen will show you what is behind it and if you are quick enough hit pause on your keyboard to freeze the post so you can read it.
Aug 17, 2003
Do you KNOW beyond doubt that the "noise" will go away if you change BIOS versions?
Have Dell specifically stated this is a BIOS issue?

If not, leave well alone, you have used up the laptops lives already in terms of the % of BIOS flashes that could and do go wrong.

If the BIOS flash goes wrong, your laptop is economically destroyed.

My guess as to the noise source would be an inverter section of the power supply, which would have no linkage whatever to the BIOS.
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