[ipxe-devel] wimboot improvement

Andrew Bobulsky rulerof at gmail.com
Mon Jun 20 15:04:27 UTC 2016

On Mon, Jun 20, 2016 at 8:30 AM, Michael Brown <mcb30 at ipxe.org> wrote:
> On 19/06/16 15:16, Vasyl Melnyk wrote:
>> I have an idea how to improve wimboot a little.
>> Bcd and boot.sdi can be also obtained from boot.wim the same way as
>> bootmgr.exe. So, if no bcd or boot.sdi is specified it would be logical
>> to get them from boot.wim too.
>> bcd path is *\Windows\Boot\DVD\PCAT\bcd* for non-UEFI boot and
>> *\Windows\Boot\DVD\EFI\bcd* for UEFI boot.
>> Boot.sdi path is *\Windows\Boot\DVD\PCAT\boot.sdi* and
>> *\Windows\Boot\DVD\EFI\boot.sdi* but they are the same.
> Are those files present:
> a) in the standard Windows installation .iso images for Win7/8/8.1?
> b) in the standard Windows installation .iso images for Win2008/2012?
> c) in standard WinPE images created by the WAIK or WADK?
> Michael
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Hello Michael, Vasyl,

I took a look inside of my x64 WinPE3 and 4 builds, some from the
ADK/WAIK and some ripped straight from install CDs, and couldn't
locate boot.sdi in any of them.

I couldn't find the BCD either, but I *did* find
C:\Windows\System32\BCD-Template, which is a very sparse BCD that
doesn't contain the proper values to boot WinPE... perhaps the same
technique that you use to modify the BCD for EFI vs BIOS at runtime
could be used on it?

I've attached some screenshots of BCD-Template vs. a regular WinPE BCD
to show the difference.

Regarding boot.sdi: since it's just a bare NTFS partition image
(right?), it might be possible to construct it instead of having the
boot server supply it, but that's really just a guess on my part.

Best Regards,
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