Re: Booting TrueCrypt Windows Hard Drive

[Felix Zielcke]

Am Freitag, den 13.11.2009, 18:28 +0100 schrieb Johannes Bauer:
> Dear list,
> 
> I've read a whole lot about problems booting Windows through Grub - but
> found no solution at all. By playing around with the options, I found a
> solution which *almost* works:
> 
> My main (Linux) drive is /dev/sda. / and /boot are on /sda1, i.e. (hd0,1).
> My crap (Windows) drive is /dev/sdb. There is only one partition
> /dev/sdb1. The whole drive has been encrypted with TrueCrypt.
> 
> I've copied the MBR of /dev/sdb to /boot/truecrypt.mbr. Then I used the
> following grub entry:
> 
> menuentry "Sigh" {
>       insmod drivemap
>       set root=(hd1,1)
>       drivemap (hd0) (hd1)
>       drivemap (hd1) (hd0)
>       chainloader (hd0,1)/boot/truecrypt.mbr
>       boot
> }
> 
> This gets further than all other tutorials I've read before - it makes
> Truecrypt actually ask for my password. After I've entered it
> successfully, the Windows logo comes up and it appears to be booting.
> However, after about 20 seocnds, it just resets hard. The next time I
> boot Windows (7, BTW) that way, I get a message saying that it crashed
> during bootup and if I want to use some kind of boot rescue restore
> magic. When I say yes, a textmode progressbar comes up. When it reaches
> 100%, the computer again resets hard.
> 
> I have a feeling that I'm almost there but am missing something - can
> somebody please help me?
> 
> Kind regards,
> Johannes

On launchpad someone made a bugreport where removing the search and
drivemap commands from the generated Win 7 menu entry by os-prober
breaks booting it.
So I removed drivemap command for Vista and 7.
It wouldn't make much sense if the search line would break it.

Did you try without drivemap?
You could also try to directly chainload MBR with (hd1)
Note that there's a difference if you use set root=(hd1,1) chainloader
+1 or just chainloader (hd1,1)+1
So you could also play around a bit with them.
The root device gets into %dl register and so the bootcode can make use
of that one.
If you specify the device inside chainloader command only GRUB itself
knows that one.

-- 
Felix Zielcke
Proud Debian Maintainer and GNU GRUB developer