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I'm curious what could happen if the BIOS flashing process is interrupted by a power failure, because in my region power cuts can occur. What are the possible repercussions?

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flashing the bios to update it –  Siddhartha Sinha Jan 25 '13 at 18:31
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Power the PC through a UPS for the BIOS update procedure to workaround power glitches/outages. –  sawdust Jan 25 '13 at 20:58

2 Answers 2

up vote 5 down vote accepted

Are you referring to the POST process? If so, there is absolutely no harm that comes from power being cut.

If you're referring to updating your BIOS via flashing it, then cutting power in the middle of the flash would brick your motherboard.

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yes i am talking about flashing it –  Siddhartha Sinha Jan 25 '13 at 18:27
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If you have any concern at all about power being cut during the flash, don't do it. –  Bigbio2002 Jan 25 '13 at 18:29
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@SiddharthaSinha: Some motherboards do have a recovery process in case a BIOS update is interrupted. They have a "boot block" that contains just enough code to complete the BIOS update process. (After the main BIOS is updated, the boot block is updated. The idea is to always have at least one of the main BIOS or the boot block valid at all times.) But it's not pretty. You definitely don't want to attempt a BIOS update if you don't have reliable power, unless your motherboard has dual BIOS. –  David Schwartz Jan 25 '13 at 18:34
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@Bigbio2002 Not all dual-BIOS motherboards are $300+. I purchased one made by Gigabyte from NewEgg and it cost me roughly $60. Granted, I've never had to use it so it and it wasn't a selling point for me. –  Kruug Jan 25 '13 at 18:41
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There are a few motherboards with removable BIOS chips as well, but that's pretty unusual. –  Shinrai Jan 25 '13 at 18:48

BIOS was (it is now superseded by the more modular UEFI) a piece of code to start the computer and installing its operating system. It is the first significant step of the boot process.

When you clear the BIOS code, the computer cannot boot and cannot load the operation system. Changing the code partially will make the computer unable to boot. This is what happen if the rewriting of the BIOS is interrupted.

Some manufacturers add some security to prevent BIOS loss if the BIOS get corrupted during the update process: The BIOS is duplicated into a "second BIOS" location before erasing the regular BIOS location. If the update process is interrupted, the BIOS can be restored from the copy. This is commonly named dual BIOS safety.

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