Find and mount the boot partition. Note: it is a fat partition before, linux; NOT the MBR sda1.

1. chroot into the arch installation (from live CD).

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   arch-chroot /mnt [/bin/bash]

2. Install the bootloader – grub.

   Install the packages grub and efibootmgr. GRUB is the bootloader, efibootmgr creates bootable .efi stub entries used by the GRUB installation script.

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   pacman -S grub

1. Make sure all partitions are mounted, i.e. / /boot /boot/efi

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   mount -a lsblk ---------------------------------------------------- NAME          MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT sda             8:0    0   477G  0 disk   ├─sda1          8:1    0   260M  0 part  /boot/efi ├─sda2          8:2    0    16M  0 part   ├─sda3          8:3    0 234.2G  0 part   ├─sda4          8:4    0    25G  0 part   ├─sda5          8:5    0  1000M  0 part   ├─sda6          8:6    0  20.2G  0 part   ├─sda7          8:7    0  1000M  0 part   ├─sda8          8:8    0   200M  0 part  /boot ├─sda9          8:9    0     8G  0 part  [SWAP] └─sda10         8:10   0 187.1G  0 part   └─cryptroot 254:0    0 187.1G  0 crypt /

2. Intial Ramdisk Environment

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   mkinitcpio -p linux

   Add the encrypt hook to mkinitcpio.conf: link here

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   etc/mkinitcpio.conf HOOKS="... encrypt ... filesystems ..."

3. retrieve the UUID, it is the crypto_LUK one.

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   lsblk -f blkid #or       ─sda10 crypto_LUK            1de833a9-36b8-4bab-91d6-65360080e71c        └─cryptroot       ext4       Arch Linux 63fbc4cb-fffd-488e-84fc-9b8ea8bf47f8 /

4. update /etc/default/grub

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   GRUB_CMDLINE_LINUX_DEFAULT="i915.preliminary_hw_support=1" GRUB_ENABLE_CRYPTODISK=y GRUB_CMDLINE_LINUX="cryptdevice=UUID=1de833a9-36b8-4bab-91d6-65360080e71c:cryptroot root=/dev$

5. install os-prober, only detect the correct Windows boot after boot into Linux, not from chroot with live CD.

6. configure grub

   The following steps install the GRUB UEFI application to $esp/EFI/grub, install its modules to /boot/grub/x86_64-efi, and place the bootable grubx64.efi stub in $esp/EFI/grub.

   First, tell GRUB to use UEFI, set the boot directory and set the bootloader ID. Mount the ESP partition to e.g. /boot or /boot/efi and in the following change $esp to that mount point (usually /boot):

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   # grub-install --target=i386-pc --force /dev/sda3

   The –bootloader-id is what appears in the boot options to identify the GRUB EFI boot option; make sure this is something you will recognize later. The install will create a directory of the same name under $esp/EFI/ where the EFI binary bootloader will be placed.

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   grub-mkconfig -o /boot/grub/grub.cfg #Generate initial grub config.

   Now, let’s add Windows to the GRUB menu. Edit /boot/efi/EFI/grub/grub.cfg and add the following menuentry after the Arch Linux menuentries [Note: grub boot loader does not locate Windows OS, but this is necessary for grub to load Arch Linux in my case. After I boot into arch linux, I ran sudo os-prober and update grub config.] See here for details.

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   if [ "${grub_platform}" == "efi" ]; then   menuentry "Microsoft Windows Vista/7/8/10 UEFI-GPT" {   insmod part_gpt   insmod fat   insmod search_fs_uuid   insmod chain   search --fs-uuid --set=root $hints_string $fs_uuid   chainloader /EFI/Microsoft/Boot/bootmgfw.efi   } fi

   and update the string with following output:

   $latex hints_string with the output of $ grub-probe –target=fs_uuid /boot/efi/EFI/Microsoft/Boot/bootmgfw.efi $latex fs_uuid with the output of $ grub-probe –target=hints_string /boot/efi/EFI/Microsoft/Boot/bootmgfw.efi

7. Unmount and Reboot

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   exit umount -R /mnt reboot

8. Reboot into Arch Linux

   Done! Hopefully you can choose between Windows and Arch Linux at the start. If not, just go back in with live CD and tweak more.