Beta RC3 = A bootable device has not been detected

nimnull22 · #1 27th September 2011, 05:03 PM

Dear All.

I have been trying to install Alfa, now it is Beta, and always I got the same message after reboot: "A bootable device has not been detected".

I have intel MB + 500GB HD. HD is completely empty and I do not modified anything in install process, just pressed "next".

I need advice.

Thanks.

sea · #2 27th September 2011, 05:11 PM

Hi

Did it create a bios boot partition?
Have you installed the bootloader?

Just for correctness, its Beta RC3, so its the 3rd release canditate to become beta.

nimnull22 · #3 27th September 2011, 06:47 PM

Parted tells:
disk /dev/sda: 500 GB
partition table: gpt

1 ..... bios_grub
2 ..... ext4 boot
3 ..... lvm

sea · #4 27th September 2011, 07:39 PM

Try installing it again, and test these along (one by one, so 2 tries)
1) on boot from dvd/cd, during the countdown, hit TAB and type enforce=0, continue with normal installation (next all the way)
2) When you're asked which option to choose about how to install, aktivate the checkbox in lower left: review partition table, delete the bios boot partition, and use the 'additional' space for the /boot (most likely to 501mb size).

fpmurphy · #5 27th September 2011, 08:21 PM

I too have the same problem with Beta RC2 and RC3 when I tell the F16 installer to use the whole disk and it creates a GPT containing a bios_grub (EF02) partition.

BTW, is Fedora the first distribution to use GRUB2 with a hybrid GPT? I suspect it is.

***DBelton*** · #6 27th September 2011, 08:30 PM

That is what it is supposed to do.

From what I have gathered..

If you have a BIOS system instead of an EFI system, and you have GPT formatted disks, it needs the bios boot partition. (Although I have yet to find it here on my system after I installed from the F16 alpha install. )

If your disks are formatted MBR, I don't think it requires the bios boot partition, or if you have an EFI system, I don't think it requires it, either.

on mine, I have all GPT formatted drives, and a BIOS, but it marked my /boot partition as some kind of EFI partition, (not EF02, but EF00)

What it boils down to..

If you have a system with a BIOS (not EFI)
AND GPT formatted disks,

then you will have the bios boot partition.

(Still can't figure out why grub2 requires the bios boot partition, and legacy grub didn't)

Found this note over on the arch linux site:

Quote:

GRUB2 in BIOS-GPT configuration requires a BIOS Boot Partition to embed its core.img in the absence of 32 KiB post MBR gap in GPT partitioned systems.
....

This partition is used by GRUB2 only in BIOS-GPT setups. No such partition type exists in case of MBR partitioning (at least not for GRUB2). This partition is also not required if the system is UEFI based, as no embedding takes place in that case. Neither GRUB-legacy nor SYSLINUX require this partition.
Note: This partition should be created before grub_bios-install or grub-setup is run or before the Install Bootloader step of the Archlinux installer (if GRUB2 is selected as bootloader).
MBR aka msdos partitioning specific instructions

Usually the post-MBR gap (after the 512 byte MBR region and before the start of the 1st partition) in many MBR (or msdos disklabel) partitioned systems is 32 KiB when DOS compatibility cylinder alignment issues are satisfied in the partition table. However a post-MBR gap of about 1 to 2 MiB is recommended to provide sufficient room for embedding grub2's core.img ( https://bugs.archlinux.org/task/24103 ). It is advisable to use a partitioner which supports 1 MiB partition alignment to obtain this space as well as satisfy other non-512 byte sector issues (which are unrelated to embedding of core.img).

fpmurphy · #7 27th September 2011, 08:44 PM

Quote:

Originally Posted by DBelton

That is what it is supposed to do.
If you have a BIOS system instead of an EFI system, and you have GPT formatted disks, it needs the bios boot partition.

Correct

Quote:

If your disks are formatted MBR, I don't think it requires the bios boot partition, or if you have an EFI system, I don't think it requires it, either.

Correct again. No problem with either.

Quote:

(Still can't figure out why grub2 requires the bios boot partition, and legacy grub didn't)

Because, as I understand it, the bios_grub partition is used to store the combined GRUB2 diskboot.img, kernel.img and selected modules image This concatanated image is created by grub-mkimage.

***DBelton*** · #8 27th September 2011, 08:51 PM

I kinda understand that grub2 puts things in there it does indeed need to boot.

But, what I am wondering..

If legacy grub could boot without all of that from a GPT disk, why does grub2 need it?

legacy grub is proof that the system can indeed boot from a GPT disk without using a bios boot parttiion, so why does grub2 need it?

not really complaining about having to have a bios boot partition, after all, 1-2 mb is nothing taken off the drives capacity nowadays. I am just trying to understand more about why it is actually needed, when it wasn't in the past.

fpmurphy · #9 27th September 2011, 09:11 PM

Quote:

Originally Posted by DBelton

I kinda understand that grub2 puts things in there it does indeed need to boot.
not really complaining about having to have a bios boot partition, after all, 1-2 mb is nothing taken off the drives capacity nowadays. I am just trying to understand more about why it is actually needed, when it wasn't in the past.

Technically, it is needed because that is the GRUB2 developers choose to implement it this way :-) Was it a good design? No, it was a compromise. In GRUB legacy on a MBR-partitioned disk a separate partition is not needed because there are enough empty contiguous blocks to hold the necessary code. There is no such empty contiguous blocks on a GPT-partitioned disk. As a result the image generated by grub-mkimage is placed in grub2_boot because the GRUB2 developers needed a well known place for the image. Look at grub-mkimage.c and grub-setup.c in GRUB 1.99 sources.

fpmurphy · #10 27th September 2011, 09:33 PM

Quote:

Originally Posted by DBelton

I kinda understand that grub2 puts things in there it does indeed need to boot.
not really complaining about having to have a bios boot partition, after all, 1-2 mb is nothing taken off the drives capacity nowadays. I am just trying to understand more about why it is actually needed, when it wasn't in the past.

Technically, it is needed because that is the GRUB2 developers choose to implement it this way :-) Was it a good design? No, it was a compromise. In GRUB legacy on a MBR-partitioned disk a separate partition is not needed because there are enough empty contiguous blocks to hold the necessary code. There is no such empty contiguous blocks on a GPT-partitioned disk. As a result the image generated by grub-mkimage is placed in grub2_boot because the GRUB2 developers needed a well known place for the image. Look at grub-mkimage.c and grub-setup.c in GRUB 1.99 sources.

sea · #11 27th September 2011, 08:52 PM

We're with Fedora, do you expect us to use 'old' software if new one is available?

***DBelton*** · #12 27th September 2011, 09:08 PM

I do if the old one is superior!

age of software is not an indicator of how good it is.

Where I work, we are still running programs that were written 60 years ago, and they run good, too. Very efficient and fast. Some haven't had to have any changes made to them in 50 years except to reassemble them to update the object code to run on newer systems.

***DBelton*** · #13 27th September 2011, 09:13 PM

But, legacy grub (in Fedora) could boot on a BIOS system, with a GPT disk and no bios boot partition.

So why does grub2 need more blocks on a GPT disk than legacy grub did to accomplish the same thing?

***DBelton*** · #14 28th September 2011, 12:15 AM

grub2 on a MBR disk doesn't need the separate partition, either.

legacy grub (in fedora) can boot from a GPT disk without having to create an extra partition. grub2 has to have the extra partition.

Same systems, same disks, formatted the same way.. grub legacy doesn't need the partition, grub2 does.

In both cases, the end result is booting the system, but it appears that grub2 needs more space to accomplish that task.

sea · #15 28th September 2011, 01:15 AM

Quote:

Originally Posted by DBelton

I do if the old one is superior!

age of software is not an indicator of how good it is.

I didnt say so either, but we're Fedora, bleeding edge, remember?

Just to share my F16 hd setup

Code:

bash-4.2$ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 298.1G  0 disk 
├─sda1   8:1    0   500M  0 part /boot
├─sda2   8:2    0  31.3G  0 part /
├─sda3   8:3    0  31.3G  0 part /home
├─sda4   8:4    0     1K  0 part 
└─sda5   8:5    0    16G  0 part [SWAP]

There is no bios-boot (by now, used to NEED one in Alpha stage), does that mean i have an EFI system?