Deactivation of UEFI possible? Fallback/Switch to BIOS ?

pstein

Honorable Member
#1
Currently more and more motherboards are released which support UEFI.

Assume I don't want to use UEFI (e.g. because of compatibility reasons): Can I
deactivate the UEFI features of the motherboard and switch back to "normal" BIOS?

Peter
 


Saltgrass

Excellent Member
Microsoft Community Contributor
#2
Most systems will allow you to install whichever configuration you boot to on the Install Media. The Windows 7 DVD and most flash drives have 2 boot images, one for UEFI and one for MBR. If you see the MBR option in your boot device menu, you should be able to boot to it and install in that mode.

If you can't see the MBR Install version, you may have to change a setting in the bios to allow your system to see the non-uefi options.

When you try it, let us know exactly what happens.. maybe we can recognize the symptoms if the install doesn't go smoothly.

And 32 bit Windows cannot do UEFI...
 


Joe S

Excellent Member
#3
Please post back UEFI is fairly new and most of us have not dealt with it yet.
Joe
 


Digerati

Fantastic Member
Microsoft MVP
#4
Can I deactivate the UEFI features of the motherboard and switch back to "normal" BIOS?
You can disable some UEFI features but you cannot switch back to normal BIOS because UEFI replaces the BIOS.

And 32 bit Windows cannot do UEFI...
Well, 32-bit Windows will run on UEFI based platforms - it just cannot support UEFI's advanced features. Note that most UEFI implementations support CSM (compatibility support mode) which emulates regular BIOS. As noted in this Microsoft white paper "UEFI and Windows",
UEFI isn't specific to any processor architecture. It can support modern 32-bit and 64-bit firmware device drivers. The 64-bit capability enables the system to address more than 17.2 billion gigabytes (GB) of memory from the earliest stages of boot.

Note: The 32-bit editions of Windows don't support UEFI features. Only 64-bit editions of Windows can take advantage of the features that 64-bit UEFI firmware enables. Fortunately, the CSM in current UEFI implementations enables 32-bit operating systems and other operating systems that don't support UEFI to boot on hardware that has UEFI firmware. But, operating systems that require a CSM to boot can't use UEFI-specific features because the CSM emulates earlier BIOS.
Still, the advantages of UEFI over BIOS are significant. And the advantages of 64-bit over 32-bit are too. So the best solution for the vast majority is to use 64-bit Windows on a UEFI platform - if possible.
 


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