Re: Chainloading an MS Windows installer DVD

[Randy Goldenberg]

What you seem to be trying to do is use grub to boot improperly prepared
Windows installation media.

What the media is does matter.

Please proceed as you see fit.

On Sun, Oct 22, 2023 at 1:17 PM Philip Couling <couling@gmail.com> wrote:

> Hopefully it should not matter what the media is. It's a USB, but I've
> confirmed that grub is reading from it : I can "ls" the files on it and
> find the EFI binary that way.
>
> I guess I'm looking for a little more info on what chainloader does. My
> firmware cannot read the image; I believe that is because of the UDF
> filesystem. However grub can. I'm a little unclear on whether the
> chainloader somehow asks the firmware to load the EFI binary or runs it
> itself. Otherwise I don't know why grub can see this file (ls the file) but
> not run it.
>
> On Thu, 19 Oct 2023 at 16:55, Randy Goldenberg <randy.goldenberg@gmail.com>
> wrote:
>
>> According to the link you provided, the ISO file can be used to
>> create installation media using a USB flash drive or DVD.  In the "subject"
>> field of your email you refer to "MS Windows installer DVD", but in the
>> body of your message you refer to "MS Windows Installer (on USB)".
>>
>> Please clarify what your boot media is, and describe how you created it.
>>
>> On Thu, Oct 19, 2023 at 2:36 AM Philip Couling <couling@gmail.com> wrote:
>>
>>> Hi
>>>
>>> Is there any reason why I can't chainload an MS Windows Installer (on
>>> USB)?  Currently when I try this I get "UnknownError" when I type "boot"
>>> at
>>> the grub command line.
>>>
>>> The MS Windows ISOs are a bit weird: found here:
>>> https://www.microsoft.com/en-gb/software-download/windows10ISO
>>>
>>> They are not partitioned and have a UDF filesystem instead of ISO 9660 or
>>> FAT32. So my hardware cannot directly boot this.  But I was assuming that
>>> all I would need to do would be ask grub to chainload the ISO as it has a
>>> UDF driver.
>>>
>>> I can read the Windows Boot media after I "insmod udf" and then
>>> "chainloader /efi/boot/bootx64.efi" which results in the output
>>> "/EndEntire".  But when I then type "boot" I get "UnknownError".
>>>
>>> Has anyone experienced this? Any ideas about what isn't working? I freely
>>> admit it could be a Microsoft weirdness that requires their input, I just
>>> wanted to exhaust options here first.
>>>
>>> Thanks
>>>
>>