Fedora Core 2 and dual-booting

[netviper13]

Here is a warning to all of those who may want to dual-boot Fedora Core 2 in a system with either Windows 2000 or Windows XP: Fedora has a serious known bug that will cause your XP install to be un-bootable by messing up the MBR. Apparently it is caused by the way kernel 2.6 views hard disk geometry.

If you do want to install Fedora and still have a dual-boot system, the easiest method of prevention (although it does not always work) is to force LBA use in the BIOS. Check through www.fedoraforum.org for more info on the bug.

Believe me this is a nasty one, I found out the hard way

[Kamel]

for those who don't know, if you have a windows boot disk and your MBR is messed up (windows only), you can do fdisk /mbr -- this will rebuild your MBR to some kind of default that microsoft has made.

a bit of warning, if you use grub/lilo as a boot loader (or the craptastic microsoft boot loader), this will break them and make it boot straight to windows. (well, it wont break them, just over-write the MBR, you would need to enter the grub command prompt and do setup (hdX))

[netviper13]

The fdisk trick actually doesn't work here; this bug totally hoses an install, because it physically changes the way the BIOS sees the hard drive's geometry; if the hard disk is not forced to LBA in the BIOS, Fedora's install will change its identification to C/H/S, which Windows is unable to boot from. For instance even after running the fdisk /mbr command, all I would get after POST is a message saying something to the tune of "bad system disk"; not even a complete re-install of Windows XP could fix the issue; I had to delete all partitions on the drive, repartition it, and do a full format/re-install (of course now that I've done some reading the solution would have been as simple as forcing LBA in the BIOS).

From what I've read the easiest fix (wish I would have known this when I encountered the issue), is simply to force LBA in the BIOS; for most people this has brought back their XP/2k setups. Still a scary issue though, especially since it was reported way back in FC2 Test 1 stages, and still isn't fixed even though its final version has been released.

[Kamel]

yea... /mbr isn't documented, but they teach it in the A+ class. people who are computer technitions are idiots, it's because that's what they are taught to be. of course, i already knew the material, i just wanted to take the class to "prove" i did, lol.

i never had any trouble with the /mbr switch, but then again, i've not delt much with the mbr. after 2 lilo messups that rendered my system useless, i converted to grub. this is the only time i ever used the /mbr switch, heh.

i think the mbr is an essential part of a computer that is highly neglected by windows.

[kurt454]

I just installed lilo to the superblock of the linux root partition, then added the partition to Windows' boot loader with bootpart. No messing with the mbr then.

[The_Mercenary]

humm....

I tried Fedora Core 2 a few Days ago. I used a 120GB HDD with WinXP and a second HDD for the Linux installation. I installed the Bootloader to the MBR of my Primary HDD (the Windumb one) and there was no messup... I guess no HDD > 8GB uses the old C/H/S method for addressing, so the Bios should automatically detect and use LBA mode for those HDDs bigger than 8GB.
Maybe you where using a small old HDD < 8GB for Booting?

[netviper13]

Originally Posted by The_Mercenary

humm....

I tried Fedora Core 2 a few Days ago. I used a 120GB HDD with WinXP and a second HDD for the Linux installation. I installed the Bootloader to the MBR of my Primary HDD (the Windumb one) and there was no messup... I guess no HDD > 8GB uses the old C/H/S method for addressing, so the Bios should automatically detect and use LBA mode for those HDDs bigger than 8GB.
Maybe you where using a small old HDD < 8GB for Booting?

Nope, it was a 120GB HDD and a 30GB partition on that drive. People with everything from 30GB drives to 250GB drives are having the issue. Linux is able to use C/H/S, and something Fedora Core 2 does to the partition table (it's in the way it reads hard disk geometry) causes the BIOS to see the drive in C/H/S; this is fine for Linux precisely because it can work off either LBA or C/H/S, but Windows will only boot from a drive the BIOS recognizes as LBA. That's why forcing LBA in the BIOS allowed people to again see their Windows install.

[pimzand]

Even better prevention for this problem is not to install grub in the MBR,
but in the boot partition. Check "advanced boot loader options" to do this.