Grub2 error: "Loading Operating System... Read Error"

[oldfred]

Some BIOS do not let you boot at all if there is not a boot flag on a primary partition. The error may have not been grub but a BIOS error. These BIOS seem to assume Windows as the boot flag is a Windows requirement, but grub does not use boot flag. Lilo also uses the boot flag so some Linux systems also use a boot flag.

Then the BIOS update either fixed the BIOS or changed to newer defaults so you are booting from a drive with the boot flag.

[YannBuntu]

Some BIOS do not let you boot at all if there is not a boot flag on a primary partition.

Thanks Oldfred, i didn't know this. Then I will try to add a new feature in Boot-Repair to easily solve this issue ( https://blueprints.launchpad.net/boo...-flag-presence ). What do you think about it, do you think it could be useful?
Among all the threads you have followed up, is there an example that you could link me please?

[sailor420]

Yann,

Updated info report on pastebin: http://paste.ubuntu.com/790104/

Thanks again!

[YannBuntu]

Updated info report on pastebin: http://paste.ubuntu.com/790104/

Thanks! (apparently no big change, except sdi renamed into sdc... no clue to detect a BIOS problem...)

[oldfred]

@ YannBuntu
Ubuntu's openID does not work on launch pad so I will just post this here, all from the forum anyway.

I do not know about Macs and how their efi works. Also not sure about RAID or LVM and how they work.

The BIOS on Intel motherboards (maybe others) seem to need a boot flag on a primary or else it will not let you start booting. Windows has to have a boot flag on a primary NTFS partition, grub does not use a boot flag, and lilo can use a boot flag on a logical to boot.

For MBR(msdos) disks I just normally suggest a boot flag on a primary partition, if not lilo booting. Some have the extended as the only primary and I have seen boot flags and grub installed to the PBR on that partition (the extended is still a primary). Not sure if it was an Intel but it did not cause issues with that system. Some put boot flag on logical which has no meaning unless using lilo as Windows will not directly boot a logical. meierfra was able to use lilo to directly boot a logical with XP.
I would not add boot flags to gpt drives, but check for efi and with type code ef00. If no efi partition then suggest bios_grub if no partition type ef02. I think the new UEFI systems do not have a UEFI/BIOS mode, but just check for a efi boot partition and if none found default to BIOS mode. Again not sure what Macs do?

Windows will only install to a NTFS primary partition with a boot flag if partition is created in advance, and usually Windows repairs only work on the primary boot partition which has the boot flag. Not sure how Windows 7 knows to fix c: unless it really just repairs the 100MB boot partition and then that can be used to run chkdsk or other repairs on c

But gpt needs a bios_grub partition with BIOS or the efi partition with UEFI.
The efi partition has to be first and have the boot flag. In gparted it is called a boot flag but srs5694 points out it is not the same boot flag as MBR(msdos). He has solved boot issues with gpt and Intel motherboard needing a boot flag. Some systems have created a partition labeled efi in place of the vendor utilities partition. It is not an efi partition since it is not first nor usually gpt.

Other notes from srs5694:
In GPT fdisk, ESPs have a type code of EF00. In libparted-based tools, you mark the ESP as such by setting its "boot flag." Note that the libparted "boot flag" means something entirely different under MBR, and you should not set the "boot flag" on any OS partition under GPT!

Info on not setting boot flag on gpt disks by ss5604 - April 11th, 2011, 08:32 PM
http://ubuntuforums.org/archive/inde...t-1722471.html
But I think he fixed a gpt disk with Intel that would not boot by adding a boot flag.
See srs5694 info on gpt & boot flag post - February 17th, 2011, 04:33 PM
http://ubuntuforums.org/archive/inde...t-1686929.html

Intel Boot Agent failed to find a bootable disk
http://ubuntuforums.org/archive/inde...t-1563699.html
http://www.rodsbooks.com/gdisk/bios.html
For anyone with same problems - Intel D510MO motherboard, Seagate 2TB hard drive. Tried Ubuntu 10.10, Ubuntu 10.4, desktop, server. Any version installed successfully, then a black screen with "no bootable device insert boot disk and press any key".
Problem solved by following srs5694's two posts.

Have you seen this thread with new test versions of bootinfoscript.
http://ubuntuforums.org/showthread.php?t=1897412

[YannBuntu]

Thanks a lot Oldfred, i will try to find the best way to implement this.

As a rough thought, i am thinking of adding an option (in the Advanced options of Boot-Repair) to let the user choose:
- if he wants to add a boot flag or not, (via a checkbox)
- and on which partition. (via a combobox)
The default would be:
- combobox would list all primary partitions located on MsDos disks
- default combobox entry would be the first Windows partition, else the first partition containing a non-Linux system, else the first NTFS partition
- checkbox unchecked (do not add flag) if GPT detected, or if flag detected on one primary partition of each disk

Concerning BIS, the GIT version looks promising. I could add an option in Boot-Repair to let the user choose the GIT version (instead of the stable one that would remain the default) if you think that could be useful.

[oldfred]

@YannBuntu
Your logic looks good.

I have also seen systems with more than one boot flag which cannot happen? Not sure with Windows 7 how you set it to the correct NTFS partition as Windows 7 usually has the 100MB hidden boot/repair partition and it is usually first, but not always in some custom installs.

Not sure how soon Gert will release the version of the bootinfoscript he is working on, it seems like most of the current questions are resolved, so I am hopeful that it will be soon.

[imachavel]

Running those commands does show the files--the kernel and initrd files for /boot, and the mod and cfg files for /boot/grub.

What I don't understand is why it would work with the USB key inserted, but not work when it's out. What is it looking for on the USB key?

I'll tell you the truth, I don't really know the answer to your question. I myself have had several problems with ubuntu grub. But never with dual booting linux. I had several problems dual booting windows(winblows) and linux, where the grub failed to recognize one or the other. With windows I tried repair console command line, and ran, not fix mbr, but another command which I forgot. This got the computer working for windows, but then linux partition at dev/sda, or was it dev/sdb I can't remember quit working for me. So I can the live cd, and got help from someone at this forum a long time ago, we purged grub 2 from the command line, and installed a legacy grub. Same issue still persisted. I never got it fixed. Now I run ubuntu on one partition, and linux mint on the other partition. works just fine. I use kvm and switch between this pc and another pc that runs windows 7, and on the ubuntu partition on this pc, I actually am virtualizing windows xp as guest. so far no problems.

Anyway I'm guessing that didn't help your problem too much. All your files backed up ok? Don't forget some things are impossible to fix. When you format the drive, us gparted to seperate the partitions accordingly. It might take a bit more work, but in the long run it's better, because you want contiguous partitions. Otherwise, if the partitions aren't contiguous, it will cause problems resizing partition space later. But then this probably won't effect your grub.

[imachavel]

@YannBuntu
Your logic looks good.

I have also seen systems with more than one boot flag which cannot happen? Not sure with Windows 7 how you set it to the correct NTFS partition as Windows 7 usually has the 100MB hidden boot/repair partition and it is usually first, but not always in some custom installs.

Not sure how soon Gert will release the version of the bootinfoscript he is working on, it seems like most of the current questions are resolved, so I am hopeful that it will be soon.

this was solved? what does his fdisk -l look like now? Mine looks like this:

sudo fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000ded99

Device Boot Start End Blocks Id System
/dev/sda1 * 95379456 658579455 281600000 83 Linux
/dev/sda2 658581502 976771071 159094785 5 Extended
/dev/sda5 853129216 924809215 35840000 82 Linux swap / Solaris
/dev/sda6 658581504 776222719 58820608 83 Linux
/dev/sda7 776224768 781449215 2612224 82 Linux swap / Solaris

Partition table entries are not in disk order

Disk /dev/sdb: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5b6ac646

Device Boot Start End Blocks Id System
/dev/sdb1 63 488392064 244196001 7 HPFS/NTFS/exFAT

[oldfred]

@imachavel
You do not have a boot flag on sdb1. But if you are only booting Linux with grub or grub2 and your BIOS does not have to have a boot flag, then it does not really matter. It just is in my opinion better to have a boot flag on a primary partition just as a standard so those with Windows will have it or those with BIOS that have to have it even if they do not have Windows.

If only booting with Linux and you have a NTFS partition you need to use a Windows repairCD and run chkdsk every 40-60 boots. Ubuntu runs fsck on root regularly but cannot run filechks on NTFS.