WinPE 4.0 x86 UEFI boot

[esgaroth]

I was under the impression that WinPE 4.0 x86 was capable of UEFI boot. I have so far been unable to get it to work. I have a x64 WinPE that boots fine with UEFI but the x86 version does not. Some computers will not recognize the usb drive or a cd as a bootable device if it has the x86 version on it. Some will attempt to boot but then fail with a message about winload.efi being corrupt. I know there is a minimum version of UEFI that will boot to x86 WinPE but these are all new computers and should meet that requirement. Updating the bios has not helped. I have secure boot turned off for now. Has anyone else successfully booted a x86 WinPE 4.0 with UEFI turned on? Is there any documentation somewhere that indicates this does not work?

[submix8c]

A notation here -

The quote given about the UEFI version is found here

http://social.technet.microsoft.com/Forums/en-US/W8ITProPreRel/thread/bbef87f4-85cd-4520-8c0b-d9acf6e47a61/

Booting X86 WINPE 4.0 requires that the UEFI be at least 2.3.1

You specifically said "some computers" so I have to assume that's the case.

A tutorial -

Edited April 11, 2013 by submix8c

[esgaroth]

I say some computers in the sense that they fail differently, but they all fail to boot. These are brand new computers so I wouldn't expect the UEFI to be that old. I have already read through each of those threads, I have yet to find anyone indicate that it has actually worked for them. My x64 PE boots in UEFI mode just fine. Only the x86 PE fails.

[wimb]

I just can confirm that x86 Win8 VHD fails to boot on UEFI computer, whereas x64 Win8 VHD is OK for UEFI Secure Boot.

http://www.911cd.net/forums//index.php?showtopic=25269

Edited April 13, 2013 by wimb

[cdob]

I have a x64 WinPE that boots fine with UEFI but the x86 version does not. Some computers will not recognize the usb drive or a cd as a bootable device if it has the x86 version on it.

I undertand: this require a x86 CPU like a Z2760.

http://ark.intel.com/de/products/70105/Intel-Atom-Processor-Z2760-1MB-Cache-1_80-GHz

The cpu is used at a Windows 8 tablet.

http://social.technet.microsoft.com/Forums/en-US/mdt/thread/f95f9f34-349a-4db2-8b80-f52c0bd39455/

Do you use a AMD64 CPU? http://en.wikipedia.org/wiki/X86-64

Long shot, not tested:

Copy "Windows Preinstallation Environment\x86\Media\EFI\Boot\bootia32.efi" to <USB>\EFI\Boot\bootx64.efi

[esgaroth]

I just found this in microsofts documentation:

"An x64-based Unified Extensible Firmware Interface (UEFI) computer can boot only by using x64 Windows PE boot files. This differs from BIOS. In BIOS, an x64-based computer can boot by using x86 Windows PE boot files. "

So I guess this really does only work on atom cpu's, an x64 WinPE is still required for UEFI boot on x64 cpu's.

[wimb]

[Long shot, not tested:

Copy "Windows Preinstallation Environment\x86\Media\EFI\Boot\bootia32.efi" to <USB>\EFI\Boot\bootx64.efi

EFI\Boot\bootia32.efi created by Win8 bcdboot.exe to boot x86 Win-8 VHD does not boot.

Then renamed bootia32.efi as BOOTX64.efi but again NOT working for booting x86 Win-8 VHD on UEFI computer ......

[Tripredacus]

When UEFI 2.3.1 spec was being "shopped" originally during the Vista days, the consensus was that it should only support 64bit architecture, as they expected 32bit to be long gone by the time it got adopted into the "desktop" space. By "they" it included the members of the UEFI working group (Microsoft, Intel, etc) and other manufacturers. So no formal development was made by anyone (officially) for x86 on modern UEFI... If you recall originally that Windows 8 was only supposed to be available in 64bit and 128bit but evidently the world just wasn't quite ready to let go of x86.

So to put it mildly, x86 is not designed to boot in UEFI mode... but also MS did not design Windows 98 to last into 2013 so anything's possible.

[cluberti]

Given the UEFI components in Win8 (and thus PE) require x64 (they did for Win7 as well, and even Vista), getting an x86 PE image to boot a UEFI machine in native mode properly isn't going to work.

[briangoch]

In PE 5.0 (and maybe windows 8.1 on which it is based) the x86 versions have winload.exe and winload.efi
Why would the 32-bit versions have an EFI file if they were not compatible with UEFI??

[cdob]

In PE 5.0 (and maybe windows 8.1 on which it is based) the x86 versions have winload.exe and winload.efi

Yes, that's true.

Be aware:

this requires a x86 UEFI: at some ATOM CPU

this fails at a amd64 CPU

[MagicAndre1981]

in WIn8 32Bit Windows versions are UEFI compatible. They did this to support Secure boot for the Atom Tablets with only 2GB RAM.