[SOLVED]Arch Linux / UEFI / BTRFS using Grub2 & Windows 8 in a 2nd HDD

Question

PROBLEM:
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Dear fellas
I just purchased an new HP TouchSmart 17.3" laptop that comes with Windows 8.1 pro (1 tb HDD + small SSD for cache only ) and still have space for one more HDD or SSD.
I Google a lot and read a lot but many questions emerged since seems that no one has the same scenario (maybe I pick the wrong choices) like me.
The problem is.. I didn't wish to re-install Windows 8.1 since it came with from factory.. so I purchased a 750 gb hdd and put it into the free slot to install Arch Linux in a different HDD.
As I am not familiar with UEFI what I did was to reorder the hdds. I just put the Windows HDD as second disk and the new disk (For Arch Linux) as primary and changed into Bios from UEFI to compatibility mode and installed Arch Linux into the primary one.
I reaaaally need help to add to grub the correct "path" to Windows 8.1 disk that came with UEFI..
Anyone could please help me?
Thanks in advance!
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SOLUTION:
A huge thanks to @TheSaint and other users for their help and assistance!
More sources:
http://www.kossboss.com/linux---arch-in … -grub-boot
https://www.youtube.com/watch?v=METZCp_JCec#t=146
https://bbs.archlinux.org/viewtopic.php … 1#p1390741
Step by Step Summary:
Use gdisk to create partitions on /dev/sda:
    - 512MB - EF02 type partition (for EFI boot)
    - 690GB - Linux partition for the BTRFS.
- Create an EF00 (ESP) with 512mb
- Create a Linux System partition with the rest of space
Make the FAT 32 system for EFI boot:
# mkfs.vfat -F32 /dev/sda1
Make the BTRFS partition. If it complains about existing filesystems just add a "-f":
# mkfs.btrfs -L arch -f /dev/sda2
We will make out a root subvolume for sda1, this will be a folder called root located at the root of sda2. The way we will design this is that When the system boots we will not see /root, we will be inside root. Inside root you will have all of your etc,sys,proc,whatever folders etc.
# mount /dev/sda2 /mnt
# cd /mnt
# btrfs subvolume create /mnt/root
This should show you your root
# btrfs subvolume list -a /mnt
Something like this: ID 256 gen 5 top level 5 path root
# cd /
# umount /dev/sda2
Now we will mount sda2 root subvolume as /mnt and we will dump the arch system into there with pacman. We will also enable compress to utilize btrfs compress feature.
# mount -o defaults,compress=lzo,subvol=root /dev/sda2 /mnt
NOTE: the command "mount" will not show which subvolume is mounted, to see how subvolumes are mounted you need to look inside proc (cat /proc/self/mountinfo):
# cat /proc/self/mountinfo | egrep sda2
The line for the mount of sda2 looks like this:
43 21 0:34 /root /mnt rw,relatime shared:30 - btrfs /dev/sda2 rw,compress=zlib,ssd,space_cache
We can see that the subvolume /root is mounted to /mnt from the device /dev/sda3
Notice how with regular mount command its missing:
# mount | egrep sda2
/dev/sda3 on /mnt type btrfs (rw,relatime,compress=zlib,ssd,space_cache)
Pacman will dump stuff into a boot folder, so we better mount our sda1 EFI boot partition to it. Or else all of the boot stuff will go to sda3 instead of sda1:
# cd /
# pacstrap -i /mnt base base-devel
Let us create the directory and mount the EFI partition
# cd /mnt
# mkdir -p /mnt/boot/efi
# mount /dev/sda1 /mnt/boot/efi
Let us generate the FSTAB:
# genfstab -p /mnt >> /mnt/etc/fstab
Let us chroot into the arch installation:
# arch-chroot /mnt /bin/bash
Change password:
# passwd
Then pick the right one like this and associate it with a link to /etc/localtime
# ln -s /usr/share/zoneinfo/US/Pacific /etc/localtime
Let us generate the initial RAM disk
# mkinitcpio -p linux
Let us setup the bootloader (GRUB)
# pacman -Syu grub efibootmgr
Let us generate the grub configuration
# grub-mkconfig -o /boot/grub/grub.cfg
Let us install grub into the HDD
# grub-install /dev/sda
# umount -R /mnt
# umount /mnt
# reboot
From this step you can go straight and forward with the https://wiki.archlinux.org/index.php/Beginners%27_guide
Last edited by erickwill (2014-11-21 20:41:06)

Answer 1

TheSaint wrote:As UEFI BIOS is a boot loader itself. You should make on each HDD an ESP.
When you want to start win8 you go to BIOS and chose its entry, so will do for Arch the same.
For this way I suggest you write to boot the kernel directly from the BIOS. It just take some reading on this topic
Other option you set on you second ESP the boot loader of your liking and it will try to find win8 partition.
Thanks for your reply.
For the second option, may I use the compatibility mode and install the booloader into the first partition along with Arch?
Or in case the first option is still the better option, could you pleaaaase give me some directions from the scratch? Do you have Google Hangout?
Thanks in advance.
Last edited by erickwill (2014-11-18 19:54:26)