Windows7 and Suse 11.4 dual boot, SP1 loaded, but why?

I have an HPDV7 laptop, originally came loaded with Vista on a single hdd(/dev/sda in Linux)
I added a second hdd(/dev/sdb in Linux), loaded 11.3 and set up dual boot. Has worked very well.
I later updated 11.3 to 11.4, which was a clean install of 11.4 reusing /home, which was on a separate partition.
When I finally could not stand Vista any longer, I installed Windows7 Update as an upgrade to Vista, not new install.

I have Grub installed in the MBR of /dev/sda
I have been watching the thread:
openSUSE Dual Booting with Windows 7 AND Loading Service Pack 1 for Windows 7 - Page 6
and have avoided loading SP1 until the dust settled and I got around to it.

Then last evening, I made a mistake, left Windows on (rather than sleep) and Windows Update automatically loaded SP1. This AM I was greeted by the SuSE login greeter, which means Windows had forced a reboot(as it always seems to do) and the default->11.4 was started by Grub.

I rebooted again, selected Win7 from the Grub menu, windows started up and I got a “Stage I of II Loading files” (or something like it message) which had a progress bar. Lots of disc action (led indicator), it made it just past 30% complete and rebooted again, I chose Win7 again at Grub menu and StageI continued, then rebooted again. In all, the process rebooted 4 or 5 times, but in pieces got thru Stage I and Stage II and finally to the Win7 login screen.
I logged in, and received the notification that SP1 had been successfully loaded.

That is nice, but Why?
Aside from the reboots (an unusual number I thought) I received no messages complaining about Grub being in MBR, etc.
I did not expect to get out of this with out my Partion Magic disk, so I wonder if there is something about how I got here (Vista - Win7) that might have helped or may help others.

Here is the configuration info I expect James to want:

findgrub
Root User Permissions are required, Please Enter the ...

root's password:
Find Grub Version 3.4.2 - Written for openSUSE Forums

 - reading MBR on disk /dev/sda                       ... --> Grub  found in sda MBR     => sdb2   0x83 (openSUSE)
 - searching partition /dev/sda1   *  (NTFS)          ... --> Windows7/Vista Loader found in /dev/sda1

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You can add the following entry to /boot/grub/menu.lst :

###Don't change this comment - YaST2 identifier: Original name: WindowsBootLoader###
title Windows on /dev/sda1
    rootnoverify (hd0,0)
    chainloader +1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 - searching partition /dev/sda2      (NTFS)          ...

 - reading MBR on disk /dev/sdb                       ...
 - skipping partition  /dev/sdb1      (swap)         
 - reading bootsector  /dev/sdb2      (LINUX)         ...
 - reading bootsector  /dev/sdb3      (LINUX)         ...


Note that Vista came configured with a recovery partition (D: drive) which is still in the Grub menu but no longer valid (called Windows 2)

cat /boot/grub/menu.lst
# Modified by YaST2. Last modification on Fri Aug 12 07:25:24 EDT 2011
# THIS FILE WILL BE PARTIALLY OVERWRITTEN by perl-Bootloader
# Configure custom boot parameters for updated kernels in /etc/sysconfig/bootloader

default 0
timeout 8
gfxmenu (hd1,1)/boot/message

###Don't change this comment - YaST2 identifier: Original name: linux###
title Desktop -- openSUSE 11.4 - 2.6.37.6-0.7
    root (hd1,1)
    kernel /boot/vmlinuz-2.6.37.6-0.7-desktop root=/dev/disk/by-id/ata-Hitachi_HTS543232L9A300_080821FB0403LPGJ40DA-part2 resume=/dev/disk/by-id/ata-Hitachi_HTS543232L9A300_080821FB0403LPGJ40DA-part1 splash=silent quiet showopts ipv6.disable=1 vga=0x317
    initrd /boot/initrd-2.6.37.6-0.7-desktop

###Don't change this comment - YaST2 identifier: Original name: failsafe###
title Failsafe -- openSUSE 11.4 - 2.6.37.6-0.7
    root (hd1,1)
    kernel /boot/vmlinuz-2.6.37.6-0.7-desktop root=/dev/disk/by-id/ata-Hitachi_HTS543232L9A300_080821FB0403LPGJ40DA-part2 showopts apm=off noresume edd=off powersaved=off nohz=off highres=off processor.max_cstate=1 nomodeset x11failsafe ipv6.disable=1 vga=0x317
    initrd /boot/initrd-2.6.37.6-0.7-desktop

###Don't change this comment - YaST2 identifier: Original name: windows 1###
title Windows 7 on sda1
    rootnoverify (hd0,0)
    chainloader +1

###Don't change this comment - YaST2 identifier: Original name: windows 2###
title windows 2
    rootnoverify (hd0,1)
    chainloader +1


I guess you have just proved that Windows is able to install SPs, even with grub installed in the MBR. I had wondered about that.

I’m pretty sure that Windows requires that the Windows partition be marked active for that to work. So it looks as if you have Windows set as the active partition. This won’t affect booting linux, since grub is in the MBR.