[ipxe-devel] wimboot issue with server 2012 on physical servers

Michael Brown mcb30 at ipxe.org
Fri May 16 14:55:52 BST 2014


On 15/05/14 15:12, Amit Shah wrote:
> I had contacted you regarding an iPXE issue with Windows 8 (below). I
> see a lot more people complain about this. There is a tool called Razor
> by puppet labs. This uses iPXE and people trying this out are facing
> this issue.
>
> Is there any way to escalate this ? Is it possible for you guys to take
> another look into this and find a possible solution.

I had a thought about this the other day.

The blank screen problem derives from a bug in bootmgr.exe: it will 
switch to graphical mode as soon as it determines that it can drive the 
VESA framebuffer display.  If it later finds that it doesn't have the 
fonts to display an error message, it will revert to plain text output. 
  However, it _fails_ to reconfigure the display for text output, with 
the result that the output is invisible.

It occurred to me that there is a workaround for this.  All real-mode 
calls made by bootmgr.exe go through wimboot (which is how wimboot works 
in the first place; it intercepts INT 13 and emulates a FAT32 disk).  We 
could intercept the VESA BIOS calls and pretend that the system does not 
have a VESA framebuffer.  This should cause bootmgr.exe to remain in 
text mode, which would then ensure that error messages would be visible 
without requiring any font files.

Michael


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