GPT cant find bootable drive [Solved]

mich04 · 2013-09-18 02:03:47

Hello, I am not sure as to what I am doing wrong. I setup my Linux system with GPT and my bios can not find a bootable device.
Here is what I have done

1. 1 mib bios partition
2. parted /dev/sda set 1 bios_grub on
3. modprobe dm-mod
4. grub-install --target=i386-pc --recheck --debug /dev/sda

My grub configuration works, I can boot if I put in the Arch ISO CD and select boot from hard drive. It than takes me to my grub menu and I select the and boot. Thank you ahead of time.

Last edited by mich04 (2013-09-19 01:22:40)

the.ridikulus.rat · 2013-09-18 02:54:48

http://rodsbooks.com/gdisk/bios.html

WonderWoofy · 2013-09-18 03:09:18

the.ridikulus.rat wrote:

http://rodsbooks.com/gdisk/bios.html

Agreed. I think gdisk is so much more straight forward in its usage. That and Rod Smith frequents these forums provided some amazing support for both his gptfdisk and rEFInd boot manager.

srs5694 · 2013-09-18 17:16:48

Note that the most probable source of the problem is the lack of an active/boot flag on the 0xEE partition in the MBR, and that can not be solved in gdisk; you'll need to use a (pre-2.23) version of fdisk or a recent version of parted to fix the problem. (I need to update the page to which the.ridikulus.rat pointed to cover recent changes to both of these tools.) Alternatively, many computers that have this problem actually have EFIs, not BIOSes, so you may be able to boot in EFI mode.

mich04 · 2013-09-19 00:35:18

You know I am not sure as to if my laptop has EFI, I do not see it in the bios. Here is my setup

Acer aspire 5315 the motherboard is LA-3551P.

I would agree that the partition does not have a boot flag, I will say I have ran usb installations just fine. Ubuntu, Arch, Kali, slitaz, puppylinux. and those were not set up with GPT. Now when I have used cfdisk from the install CD to try and set the boot flag, but it only saw one giant GPT partition.

cfr · 2013-09-19 00:55:06

mich04 wrote:

I would agree that the partition does not have a boot flag, I will say I have ran usb installations just fine. Ubuntu, Arch, Kali, slitaz, puppylinux. and those were not set up with GPT. Now when I have used cfdisk from the install CD to try and set the boot flag, but it only saw one giant GPT partition.

I think that is what you want. Certainly fdisk sees it that way in older versions - that's why the suggestion above specified an older version if you used fdisk. Even though you shouldn't use these tools to modify GPT disks normally, using them for this should be safe.

mich04 · 2013-09-19 01:08:47

Note that the most probable source of the problem is the lack of an active/boot flag on the 0xEE partition in the MBR

Now I did see in gdisk if you type x (extra functionality (experts only)) than type a (set attributes) select the partition I can set "legacy BIOS bootable". To me this is the same as what you are describing. I did try this with the 1 mib bios partition and my boot partition neither scenario worked.

@cfr if I am reading correctly you are suggesting that I set the boot flag for the one partition that fdisk sees, with fdisk. I will try that.

mich04 · 2013-09-19 01:22:12

Wow that is very interesting, so I used fdisk on the Arch install CD that I have, and I set the boot flag for the GPT partition, which fdisk saw as /dev/sda1. Now it boots. It is very interesting So GPT stands alone on the disk just like a filesystem?

cfr · 2013-09-19 01:25:05

mich04 wrote:

Note that the most probable source of the problem is the lack of an active/boot flag on the 0xEE partition in the MBR
Now I did see in gdisk if you type x (extra functionality (experts only)) than type a (set attributes) select the partition I can set "legacy BIOS bootable". To me this is the same as what you are describing. I did try this with the 1 mib bios partition and my boot partition neither scenario worked.

Since srs5694 said this couldn't be fixed with gdisk and since srs5694 wrote gdisk, I am pretty sure this is not equivalent.

@cfr if I am reading correctly you are suggesting that I set the boot flag for the one partition that fdisk sees, with fdisk. I will try that.

Yes. I don't entirely understand it but you are not setting the flag on one of the GPT partitions at all, I don't think. I think you are rather manipulating the protective MBR but srs5694 will probably explain this and I could be wrong. I am sure using an older fdisk (that just sees the one large partition) is what is intended to set the flag, though, as I tried this myself. (It didn't fix the issue on my machine but that's another story.)

mich04 · 2013-09-19 01:54:29

Since srs5694 said this couldn't be fixed with gdisk and since srs5694 wrote gdisk, I am pretty sure this is not equivalent.

Sorry I did not know srs5694 wrote the program, your assessment is probably true then. I would also agree that I am manipulating the MBR rather than the 1 mib partition. I appreciate everyones help on this matter.

srs5694 · 2013-09-19 19:51:40

cfr wrote:

mich04 wrote:
Note that the most probable source of the problem is the lack of an active/boot flag on the 0xEE partition in the MBR
Now I did see in gdisk if you type x (extra functionality (experts only)) than type a (set attributes) select the partition I can set "legacy BIOS bootable". To me this is the same as what you are describing. I did try this with the 1 mib bios partition and my boot partition neither scenario worked.
Since srs5694 said this couldn't be fixed with gdisk and since srs5694 wrote gdisk, I am pretty sure this is not equivalent.

Quite correct.

I don't entirely understand it but you are not setting the flag on one of the GPT partitions at all, I don't think. I think you are rather manipulating the protective MBR but srs5694 will probably explain this and I could be wrong.

You're exactly correct. GPT includes a "protective MBR," which is a (mostly) legal MBR partition table, the purpose of which is to keep GPT-unaware tools from messing with the disk. Unfortunately, some BIOSes look for a bootable MBR partition and refuse to boot if they don't see one. Some EFIs also use a bootable MBR partition or other partitioning details to determine whether to boot in EFI mode or in BIOS mode, which can have the same effect. In any event, setting the active/boot flag on the protective partition in the MBR enables some computers to boot from a GPT disk in BIOS mode. Technically, setting this flag is a violation of the GPT spec, but as a pratical matter it's required for some configurations.

Note that this is entirely different from setting the "legacy BIOS bootable" attribute on a partition using gdisk; that action modifies a GPT-specific attribute without touching the MBR's 0xEE partition. The "legacy BIOS bootable" attribute is used by SYSLINUX's GPT version to identify the partition to which it should transfer control. This is similar to the boot/active flag on MBR, but it's not something that any firmware cares about, to the best of my knowledge.

Arch Linux

#1 2013-09-18 02:03:47

GPT cant find bootable drive [Solved]

#2 2013-09-18 02:54:48

Re: GPT cant find bootable drive [Solved]

#3 2013-09-18 03:09:18

Re: GPT cant find bootable drive [Solved]

#4 2013-09-18 17:16:48

Re: GPT cant find bootable drive [Solved]

#5 2013-09-19 00:35:18

Re: GPT cant find bootable drive [Solved]

#6 2013-09-19 00:55:06

Re: GPT cant find bootable drive [Solved]

#7 2013-09-19 01:08:47

Re: GPT cant find bootable drive [Solved]

#8 2013-09-19 01:22:12

Re: GPT cant find bootable drive [Solved]

#9 2013-09-19 01:25:05

Re: GPT cant find bootable drive [Solved]

#10 2013-09-19 01:54:29

Re: GPT cant find bootable drive [Solved]

#11 2013-09-19 19:51:40

Re: GPT cant find bootable drive [Solved]

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