Syslinux with GPT

Jimbo · 2014-09-14 13:43:49

Following beginners guide @ part - https://wiki.archlinux.org/index.php/Be … e#Syslinux

ran cmd

pacman -S gptfdisk
pacman -S syslinux

I am slightly confused as it tells me to run the following

syslinux-install_update -iam

Docs state options are

Install the syslinux package and then use the syslinux-install_update script to automatically install the bootloader (-i), mark the partition active by setting the boot flag (-a), and install the MBR boot code (-m):

The confusion is because at the start of the docs precisely here - https://wiki.archlinux.org/index.php/Be … table_type

It states

You have to choose between GUID Partition Table (GPT) and Master Boot Record (MBR)

So do I run the following

syslinux-install_update -iam

Or do I omit the m as we dont are not using MBR but GPT

syslinux-install_update -ia

Last edited by Jimbo (2014-09-14 13:57:39)

nomorewindows · 2014-09-14 14:06:19

If you aren't running UEFI, it'll be a protective mbr. The thing that syslinux is installing is the syslinux boot loader. And this is usually tied with /boot.

Jimbo · 2014-09-14 14:09:43

nomorewindows wrote:

If you aren't running UEFI, it'll be a protective mbr. The thing that syslinux is installing is the syslinux boot loader. And this is usually tied with /boot.

I am not running UEFI, but what do you mean a protective mbr?

Why is any form of MBR being talked about when I choose GPT?

nomorewindows · 2014-09-14 14:10:53

It has to comply with BIOS.

Jimbo · 2014-09-14 14:28:45

nomorewindows wrote:

It has to comply with BIOS.

Ok, in that case I ran the cmd

syslinux-install_update -iam

umount /dev/sda1 /mnt
umount /dev/sda2 /mnt/home

exit

reboot

After rebooting I get a flashing

_

character appear, but nothing happens, then my system goes directly into the BIOS.

Manually choosing the HD (which is not listed in bios as sda1, but I only have 2 connected) brings up the same flashing character but then returning into BIOS.

Do you know what the problem could be here?

My last modifications within the boot image with mounted partitions were

syslinux-install_update -iam
nano /boot/syslinux/syslinux.cfg

LABEL arch
...
APPEND root=/dev/sda1 rw
...

The guide assumes all will work after this last step, but it doesn't.

Last edited by Jimbo (2014-09-14 14:30:09)

nomorewindows · 2014-09-14 14:49:18

Did you convert your mbr to gpt with gdisk? What does the output of fdisk show as to which disklabel is being used?

Jimbo · 2014-09-14 15:00:26

nomorewindows wrote:

Did you convert your mbr to gpt with gdisk? What does the output of fdisk show as to which disklabel is being used?

Yes I did.

fdisk -l

...
Disk /dev/sda: 1.8 TiB
Disklabel type: gpt
...

CarlD · 2014-09-14 15:20:46

https://wiki.archlinux.org/index.php/Sy … tion_table

This includes the appopriate command for GPT:

# syslinux-install_update -i -m

Last edited by CarlD (2014-09-14 15:21:47)

Jimbo · 2014-09-14 15:28:55

CarlD wrote:

https://wiki.archlinux.org/index.php/Sy … tion_table
This includes the appopriate command for GPT:
# syslinux-install_update -i -m

Tried this command, along with the command without the -m
returns

Successfully installed BIOS...

After umount, exit, reboot

I still just get a flashing _ character then the system goes into the BIOS

CarlD · 2014-09-14 15:50:15

Did you do:

# sgdisk /dev/sda --attributes=1:set:2
# sgdisk /dev/sda --attributes=1:show

Beforehand to make it BIOS bootable?

Jimbo · 2014-09-14 16:50:04

CarlD wrote:

Did you do:
# sgdisk /dev/sda --attributes=1:set:2
# sgdisk /dev/sda --attributes=1:show
Beforehand to make it BIOS bootable?

No I did not, would you mind telling me where it states to do that in the beginner guide? I do not recall reading those cmds and cannot find them on that page.

CarlD · 2014-09-14 18:40:44

That would be in the Syslinux/GPT link I posted earlier.

To be frank, there is no point in using GPT for a BIOS system; GPT is intended for UEFI. This is why you are having such trouble installing Syslinux, as GPT needs further modification to work with BIOS systems. My advice would be to stick with the MBR table type, which it originally was (as it is for BIOS systems). You can use cfdisk as your partitioning tool.

teateawhy · 2014-09-14 20:45:12

CarlD wrote:

To be frank, there is no point in using GPT for a BIOS system;

GPT has multiple advantages over MBR, in short, GPT is the more modern variant.

GPT is intended for UEFI.

GPT can theoretically be used with BIOS, and MBR can theoretically used with UEFI. But a number BIOS/UEFI versions are faulty and can not handle these combinations. Also windows can not handle these combinations, but linux can.

GPT needs further modification to work with BIOS systems.

No. You can not change the GPT layout to make the faulty BIOS understand GPT, you would have to change the BIOS by flashing a new different one.

My advice would be to stick with the MBR table type, which it originally was (as it is for BIOS systems). You can use cfdisk as your partitioning tool.

Yes.

CarlD · 2014-09-14 21:15:08

GPT has multiple advantages over MBR, in short, GPT is the more modern variant.

To put it mildly! The advantages are enormous, although can only really be fully exploited by UEFI systems (e.g. BIOS systems can't handle over 2TB even though GPT can).

GPT can theoretically be used with BIOS, and MBR can theoretically used with UEFI. But a number BIOS/UEFI versions are faulty and can not handle these combinations. Also windows can not handle these combinations, but linux can.

GPT is still intended for UEFI.

No. You can not change the GPT layout to make the faulty BIOS understand GPT, you would have to change the BIOS by flashing a new different one.

My mistake; was thinking of UEFI legacy boot :-P

Last edited by CarlD (2014-09-14 21:17:01)

Jimbo · 2014-09-14 22:58:46

sgdisk /dev/sda --attributes=1:set:2
sgdisk /dev/sda --attributes=1:show

Applied these, returned successful msgs.

However still does not boot.

The official docs state - https://wiki.archlinux.org/index.php/Be … ion_scheme

If you have a BIOS motherboard (or plan on booting in BIOS compatibility mode) and you want to setup GRUB on a GPT-partitioned drive, you will need to create an extra BIOS Boot Partition of size 1 or 2 MiB and EF02 type code. Syslinux does not need one.

Yet on the Syslinux page it states

Bit 2 of the attributes ("legacy_boot" attribute) needs to be set for the /boot partition:.

Is this the /boot partition talked about in my first quote from the beginners guide which we apparently do not need?

I recall mounting/creating

mount /dev/sda1 mnt
mkdir /mnt/home
mount /dev/sda2 /mnt/home

Confused.

Last edited by Jimbo (2014-09-15 13:58:15)

dawja · 2014-09-20 17:16:42

Hi I hope your still not having problems. I cant remember where I read it but if I find it ill post a link. the -m option is needed its not to be confused with Master Boot Record as in partioning, but I ran it on my GPT and it works. That confuesd me as well. Hope this helps

Arch Linux

#1 2014-09-14 13:43:49

Syslinux with GPT

#2 2014-09-14 14:06:19

Re: Syslinux with GPT

#3 2014-09-14 14:09:43

Re: Syslinux with GPT

#4 2014-09-14 14:10:53

Re: Syslinux with GPT

#5 2014-09-14 14:28:45

Re: Syslinux with GPT

#6 2014-09-14 14:49:18

Re: Syslinux with GPT

#7 2014-09-14 15:00:26

Re: Syslinux with GPT

#8 2014-09-14 15:20:46

Re: Syslinux with GPT

#9 2014-09-14 15:28:55

Re: Syslinux with GPT

#10 2014-09-14 15:50:15

Re: Syslinux with GPT

#11 2014-09-14 16:50:04

Re: Syslinux with GPT

#12 2014-09-14 18:40:44

Re: Syslinux with GPT

#13 2014-09-14 20:45:12

Re: Syslinux with GPT

#14 2014-09-14 21:15:08

Re: Syslinux with GPT

#15 2014-09-14 22:58:46

Re: Syslinux with GPT

#16 2014-09-20 17:16:42

Re: Syslinux with GPT

Board footer