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[SOLVED] “No boot disk found” when rebooting on AMD64
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ccconnor
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PostPosted: Tue Jul 26, 2016 5:36 am    Post subject: [SOLVED] “No boot disk found” when rebooting on AMD64 Reply with quote

I have followed the Gentoo handbook for AMD64 architectures up to the end of this page. Every time I do the necessary commands, my computer says “No boot disk found or the disk has failed” although I have tried to install Gentoo once for BIOS and and once for UEFI, and both have failed.

I don’t know if my computer from 2010 prefers to boot in BIOS or UEFI mode, and I don’t know how to check from a live environment (search results seem to suggest I need an installed operating system to check). I am also using the default partitions the handbook uses (/dev/sda1 BIOS boot, /dev/sda2 GRUB, /dev/sda3 swap, /dev/sda4 root). If you need any more information, just ask.


Last edited by ccconnor on Fri Jul 29, 2016 11:17 pm; edited 1 time in total
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snkmoorthy
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PostPosted: Tue Jul 26, 2016 5:46 am    Post subject: Reply with quote

Best you ask at Gentoo IRC for quicker response times.

https://www.gentoo.org/get-involved/irc-channels/
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Hu
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PostPosted: Wed Jul 27, 2016 1:31 am    Post subject: Reply with quote

That page describes several different bootloaders. Which one did you use? Please post its configuration file, the commands you ran to install it, and their output.
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ccconnor
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PostPosted: Wed Jul 27, 2016 2:47 am    Post subject: Reply with quote

snkmoorthy wrote:
Best you ask at Gentoo IRC for quicker response times.

https://www.gentoo.org/get-involved/irc-channels/
Thanks, but the IRC seems to be just as slow.
Hu wrote:
That page describes several different bootloaders. Which one did you use? Please post its configuration file, the commands you ran to install it, and their output.
I used GRUB2, and I currently have it installed for UEFI. I had installed it like so:
Code:
root # echo GRUB_PLATFORMS="efi-64" >> /etc/portage/make.conf
root # emerge --ask sys-boot/grub:2
root # grub2-install --target=x86_64-efi --efi-directory=/boot
root # grub2-mkconfig -o /boot/grub/grub.cfg
My GRUB2 configuration is here. I do not know how to get the output of my GRUB2 being installed when I have already installed it (other than reinstalling, which I feel is unnecessary). Maybe an install output log file somewhere? If you could tell me where such a file is, thanks.
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Section_8
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PostPosted: Wed Jul 27, 2016 5:12 am    Post subject: Reply with quote

Quote:
I don’t know if my computer from 2010 prefers to boot in BIOS or UEFI mode
You should be able to set this in your BIOS settings. In my mobo, there is a Legacy/UEFI boot mode setting - if you can't find anything like that, your system is probably BIOS.
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ccconnor
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PostPosted: Wed Jul 27, 2016 5:22 am    Post subject: Reply with quote

Section_8 wrote:
You should be able to set this in your BIOS settings. In my mobo, there is a Legacy/UEFI boot mode setting - if you can't find anything like that, your system is probably BIOS.
Doesn’t seem to be there. However, when I go to the boot menu so I can choose which device to boot from (not into the BIOS setup), there is an “EFI:” prepended before the name of my HDD. Does this mean anything?
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NeddySeagoon
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PostPosted: Wed Jul 27, 2016 10:22 pm    Post subject: Reply with quote

ccconnor,

No boot disk found means that you have not set the bootable flag on exactly one partition on your HDD.
You have one of these brain dead BIOSes that checks.

If you have used a GPT disk label, the boot flag needs to be set in the protective MSDOS partition table, as thats all the BIOS can see.
All the usual partitioning tools can set/clear this flag.
Your install will not be harmed as long as all you do is change bootable flags
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Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
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ccconnor
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PostPosted: Wed Jul 27, 2016 10:58 pm    Post subject: Reply with quote

NeddySeagoon wrote:
ccconnor,

No boot disk found means that you have not set the bootable flag on exactly one partition on your HDD.
You have one of these brain dead BIOSes that checks.

If you have used a GPT disk label, the boot flag needs to be set in the protective MSDOS partition table, as thats all the BIOS can see.
All the usual partitioning tools can set/clear this flag.
Your install will not be harmed as long as all you do is change bootable flags
Ah, I assume you’re referring to this? I had already done that through the fdisk -t dos /dev/sda command, except when I typed in a, fdisk automatically toggled the boot flag of partition 1 without asking me which partition. I wrote the changes, however my computer still does not detect the boot disk (maybe because I installed it as UEFI), but thanks for the help.
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NeddySeagoon
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PostPosted: Thu Jul 28, 2016 5:09 pm    Post subject: Reply with quote

ccconnor,

When you say you installed for UEFI, do you mean you selected a GPT disk label?

That would tie in with your
Quote:
fdisk automatically toggled the boot flag of partition 1 without asking
because there is only a single partition there.
There are a small number of systems that not only check the bootable flag, they check the partition type code too.
Some Dells are known not to boot from a partition table with a singre ently of type ee, which means that a GPT partition table exists.

The test is simple. Change the partition type byte (in the MSDOS partition table, to something that the BIOS is expecting and see if the error goes away.
The system slill won't boot as the kernel will not see the GPT table, but the error will change.

The fix is not so trivial. You must reinstall using an MSDOS disk label.

-- edit --
That fix is a bit hash. You need to back up the install and restore it to an MSDOS partitioned HDD.
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Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
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ccconnor
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PostPosted: Thu Jul 28, 2016 6:47 pm    Post subject: Reply with quote

NeddySeagoon wrote:
ccconnor,

When you say you installed for UEFI, do you mean you selected a GPT disk label?

That would tie in with your
Quote:
fdisk automatically toggled the boot flag of partition 1 without asking
because there is only a single partition there.
There are a small number of systems that not only check the bootable flag, they check the partition type code too.
Some Dells are known not to boot from a partition table with a singre ently of type ee, which means that a GPT partition table exists.

The test is simple. Change the partition type byte (in the MSDOS partition table, to something that the BIOS is expecting and see if the error goes away.
The system slill won't boot as the kernel will not see the GPT table, but the error will change.

The fix is not so trivial. You must reinstall using an MSDOS disk label.
I did not necessarily mean having selected a GPT partition table when I said “installed for UEFI” but, yes, I have selected a GPT disk label. My system is a Gateway one, by the way.

So I assume I have to do fdisk -t dos /dev/sda, then type in t, but I don’t know which hexcode would be an MSDOS partition label.
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NeddySeagoon
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PostPosted: Thu Jul 28, 2016 6:55 pm    Post subject: Reply with quote

ccconnor,

fdisk will list the partition types.

NTFS, VFAT, or linux will do for the test.
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ccconnor
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PostPosted: Thu Jul 28, 2016 11:16 pm    Post subject: Reply with quote

NeddySeagoon wrote:
ccconnor,

fdisk will list the partition types.

NTFS, VFAT, or linux will do for the test.
Changed the partition type to hexcode c, and now I get a screen like this:
Code:
GRUB loading.
Welcome to GRUB!

error: no such partition.
Entering rescue mode...
grub rescue>
What do I do now?
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NeddySeagoon
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PostPosted: Fri Jul 29, 2016 7:33 pm    Post subject: Reply with quote

ccconnor,

I was afraid that would happen. Your BIOS is not only checking the bootable flag on the MSDOS partition, its also checking the partition type.
When the partition type is 0xee, which means that the disk really uses GPT, you get the no boot disk found message.
Changing the 0xee to 0x0c keers the BIOS happy but confuses grub and if you get past grub, it will confuse the kernel.

The right thing to do is to back up your install, set up the HDD with an MSDOS disk label, then restore your install.
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NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
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ccconnor
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PostPosted: Fri Jul 29, 2016 11:16 pm    Post subject: Reply with quote

NeddySeagoon wrote:
ccconnor,

I was afraid that would happen. Your BIOS is not only checking the bootable flag on the MSDOS partition, its also checking the partition type.
When the partition type is 0xee, which means that the disk really uses GPT, you get the no boot disk found message.
Changing the 0xee to 0x0c keers the BIOS happy but confuses grub and if you get past grub, it will confuse the kernel.

The right thing to do is to back up your install, set up the HDD with an MSDOS disk label, then restore your install.
I have done just that. Thank you for all the help.
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NeddySeagoon
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PostPosted: Sat Jul 30, 2016 10:02 am    Post subject: Reply with quote

ccconnor,

I'm curious to know what system you have. I've seen this only once before, on a Dell laptop.
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NeddySeagoon

Computer users fall into two groups:-
those that do backups
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ccconnor
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PostPosted: Sun Jul 31, 2016 9:40 pm    Post subject: Reply with quote

NeddySeagoon wrote:
ccconnor,

I'm curious to know what system you have. I've seen this only once before, on a Dell laptop.
I have a Gateway-manufactured system with an Acer BIOS, and I got it in 2010.
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