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Caution on multi-booting--weird partition results

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I was in the process of setting up a SL/Win7/Ubuntu system using the guide found here:

http://www.tonymacx86.com/viewtopic.php?f=81&t=20872

I had Win7 and SL more or less running, and decided to add Ubuntu. I probably missed an important step, and managed to largely make my Windows partition unreadable. After some looking around, I learned that part of the problem is that OSX creates a hybrid MBR. When it works, it's fine, but if things get hosed, you could be in line for a painful rebuild.

Take a look at what one expert says about hybrid MBRs:

http://www.rodsbooks.com/gdisk/hybrid.html

I think I will (once I am able to boot anything SL...right now I can't even get iBoot to load) simply switch boot priority to avoid this problem--OSX on one physical drive, Win7 and Ubuntu on another.
 

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solstice said:
I was in the process of setting up a SL/Win7/Ubuntu system using the guide found here:

viewtopic.php?f=81&t=20872

I had Win7 and SL more or less running, and decided to add Ubuntu. I probably missed an important step, and managed to largely make my Windows partition unreadable. After some looking around, I learned that part of the problem is that OSX creates a hybrid MBR. When it works, it's fine, but if things get hosed, you could be in line for a painful rebuild.

Take a look at what one expert says about hybrid MBRs:

http://www.rodsbooks.com/gdisk/hybrid.html

I think I will (once I am able to boot anything SL...right now I can't even get iBoot to load) simply switch boot priority to avoid this problem--OSX on one physical drive, Win7 and Ubuntu on another.
If you installed per the guide linked, then you had no hybrid MBR partition because the entire drive was formatted GUID.
If you fail to install Ubuntu properly, then it will mess up everything. You must install grub to the root "/" or "/boot" partition and you must use gptsync to resync the partitions or it will be unbootable by anything except the Grub boot loader. You must also use an external boot loader to boot back into OS X and re-install Chimera / Chameleon in order to get your drive to boot again after resyncing the partitions.
Better to put Ubuntu on a drive by itself and have OS X and Win7 share a drive.
 
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Thanks for the info. I believe I followed the guide instructions at least as far as the Windows installation, and other than the bump I'll describe in a moment, I mostly followed the part through Ubuntu. My problems seemed to start from a hiccup in the Ubuntu istallation--it choked once, and then once I repartitioned and loaded it, Windows was unbootable and unrecoverable. Rod's diagnosis was that the problem was a hybrid MBR. I wonder if Ubuntu created it during my first, aborted, installation?
 

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solstice said:
Thanks for the info. I believe I followed the guide instructions at least as far as the Windows installation, and other than the bump I'll describe in a moment, I mostly followed the part through Ubuntu. My problems seemed to start from a hiccup in the Ubuntu istallation--it choked once, and then once I repartitioned and loaded it, Windows was unbootable and unrecoverable. Rod's diagnosis was that the problem was a hybrid MBR. I wonder if Ubuntu created it during my first, aborted, installation?
Forget hybrid MBR. With the methods in the guide there is no possible way to get a MBR unless you failed to do step 1f properly. It clearly states to format GUID - NOT MBR. If you had an aborted install of Ubuntu, then that is probably the source of the problem.
After install of Ubuntu, any other OS will be unbootable and unrecoverable until you re-sync the partitions - use gptsync.
You need to then re-install Chameleon or other bootloader to the hard drive to boot without iBoot.
 
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