Issue with boot != root and chainloading

[Andy Kittner <andkit@gmx.de>]

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Hi all,

First of all I hope I've come to the right place with my little bug 
(from what I've read this list seems to be preferred to the tracker?).

Anyway here it goes: I have two hard drives in my notebook, and tried 
installing grub (svn r1724) with it's root on the second one (/dev/sdb5 
to be precise)

    grub-install /dev/sda

Everything went smooth, however after rebooting I get dropped in rescue 
mode with this message: "unknown device fd1,5"

As I had a bit of free time I investigated where the fd1 might come 
from and it turned out that grub_root_device seems to contain a wrong 
value:

diff --git a/grub2/kern/i386/pc/init.c b/grub2/kern/i386/pc/init.c
index e47cbfd..01e8d7d 100644
--- a/grub2/kern/i386/pc/init.c
+++ b/grub2/kern/i386/pc/init.c
@@ -236,8 +236,10 @@ grub_machine_init (void)
   void
   grub_machine_set_prefix (void)
   {
+  char *prefix = make_install_device();
     /* Initialize the prefix.  */
-  grub_env_set ("prefix", make_install_device ());
+  grub_env_set ("prefix", prefix);
+  grub_printf("0x%x, 0x%x, %s\n", grub_boot_drive, grub_root_drive, prefix ? prefix : "<null>");
   }
   
   void


With this patch it prints
"0x80, 0x1, (fd1,5)/boot/grub/"
and I presume the 0x1 should actually be a 0x81, however I have no clue 
why it is wrong and as it seems to be initialized in startup.S I thought 
I'd leave it to the experts at this point. 

After:

    set prefix=(hd1,5)/boot/grub
    set root=(hd1,5)
    insmod normal
    normal

I end up in the menu and can boot my linux kernels just fine.

Now for my second problem:
If I try to chainload grub legacy on another partition it just hangs 
after printing "GRUB ". The command I used to do this was:
    chainloader (hd0,5)+1

Chainloading my windows partition using:
    chainloader (hd0,1)+1
has a similar result, namely a blank screen with a blinking cursor.

I would need some advice on how to debug this, but I guess the first 
interesting bit would be if this is broken for others as well, or just 
a peculiarity of my system.


Best regards
Andy

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