Arch: Repair notes

If repairing a virtual machine:

    0. If settings are greyed out then start virtual machine and perform [$ sudo shutdown now].

    1. Settings > Storage:

        Controller: IDE

            Click CD icon > select archlinux iso.

    2. Disable EFI boot:    <-- The Arch ISO won't boot in UEFI mode for whatever reason. No issue on computer but this affects virtual machines i think.

        Settings > System:

            [ ] Enable EFI (special OSes only)    <-- The CD won't boot with EFI enabled.

    3. Start virtual machine.

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0. Boot with Arch usb plugged in.

1. Select "Arch Linux install medium (x86_64, BIOS)

2. Connect to the internet from the Arch main-menu:    <-- Needed if using wi-fi to get online because [$ nmtui] won't work after arch-chroot for whatever reason.

    For wireless and WWAN, make sure the card is not blocked with rfkill.

    1. Connect to the network:

        Ethernet:

            Plug in the cable.

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        Wi-Fi:

            Start the interactive prompt:

                $ iwctl    <-- NOTE: Use $ exit or Ctrl + D to quit the interactive prompt.

                NOTE: You can use all commands as command line arguments without entering an interactive prompt, e.g. [$ iwctl device wlan0 show].

                NOTE: To list all available commands use [$ help].

            Connect to a network:

                1. List all Wi-Fi devices:

                    $ device list

                2. If the device or its corresponding adapter is turned off, turn it on:

                    $ device <device> set-property Powered on
                    $ adapter <adapter> set-property Powered on

                3. Scan for networks:

                    $ station <device> scan
                    $ station <device> get-networks

                4. Connect to a network:

                    $ station <device> connect "Case-Sensitive SSID"

                    NOTE: The command line equivalent: [$ iwctl --passphrase <pw> station <device> connect SSID]

                    NOTE: iwd automatically stores network passphrases in /var/lib/iwd/ and uses them to auto-connect in the future.
                          iwd only supports PSK pass-phrases from 8 to 63 ASCII-encoded characters. The following error message will be given if the requirements are not met: PMK generation failed. Ensure Crypto Engine is properly configured.

                    NOTE: For automatic IP and DNS configuration via DHCP, you have to manually enable the built-in DHCP client or configure a standalone DHCP client.

                    NOTE: The user interface supports autocomplete. Typing station or connect and Tab Tab, the available devices or networks are displayed,
                          Type the first letters of the device or network and Tab to complete.

                    Connect to a network using WPS/WSC:

                        If your network is configured such that you can connect to it by pressing a button:

                            $ wsc list

                        If your device appeared in the above list:

                            $ wsc <device> push-button

                            And push the button on your router. The procedure works also if the button was pushed beforehand, less than 2 minutes earlier.

                        If your network requires to validate a PIN number to connect that way, check the $ help command output to see how to provide the right options to the wsc command.

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                1. Disconnect from a network:

                    $ station <device> disconnect

                2. Show device and connection information:

                    $ device <device> show

                3. Display the connection state:

                    $ station <device> show

                4. Manage known networks:

                    $ known-networks list

                5. Forget a known network:

                    $ known-networks "SSID" forget

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    2. Ensure your network interface is listed and enabled:

        $ ip link

    3. The connection may be verified with ping:

        $ ping -c 3 archlinux.org

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1. Get drive names:

    WARNING: If you are here and did not get online first, then read from the top of this file again.
             If you arch-chroot before iwctl then you are not getting online (with wi-fi) because iwctl will not work after arch-chroot for some reason.

    $ lsblk    <-- Or [$ df -Th] [$ mount] [$ fdisk -l]

    Or

    $ lsblk -o NAME,MOUNTPOINT,LABEL,FSTYPE,SIZE,UUID    <-- Displays more drive info.

2. Mount the file systems:

    EXT4 Notes:

        Mount the root partition to "/":

            $ mount /dev/<root partition> /mnt/

        Mount the home partition to "/home":

            $ mount /dev/<home partition> /mnt/home

        Mount the EFI partition to "/efi":

            If using "/efi" location:

            $ mkdir -p /mnt/efi
            $ mount /dev/<efi partition> /mnt/efi

            Or if using "/boot/efi" location:

            $ mkdir -p /mnt/boot/efi
            $ mount /dev/<efi partition> /mnt/boot/efi

    BTRFS Notes:    <-- WARNING: Untested AI generated notes.

        1. Identify partitions:
            lsblk -f

            Example layout:
                sda1   btrfs   root
                sda2   btrfs   home
                sda3   vfat    EFI

        2. Create mount points:
            mkdir -p /mnt
            mkdir -p /mnt/home
            mkdir -p /mnt/efi

        3. Check for existing subvolumes:
            btrfs subvolume list /dev/sda1
            btrfs subvolume list /dev/sda2

        4. Mount root and home:
            NOTE: Adjust the subvolume names in the mount commands to match what [$ btrfs subvolume list] shows.

            mount -o subvol=@ /dev/sda1 /mnt            # root
            mount -o subvol=@home /dev/sda2 /mnt/home   # home, if separate partition with @ subvolume

        5. Mount EFI partition:
            mount /dev/sda3 /mnt/efi

        6. Verify mounts:
            lsblk -f

3. Check the file system is mounted correctly:

    $ lsblk    <-- Or [$ df -Th] [$ mount] [$ fdisk -l]

    Or

    $ lsblk -o NAME,MOUNTPOINT,LABEL,FSTYPE,SIZE,UUID    <-- Displays more drive info.

    NAME            MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
    sda               8:0    0    50G  0 disk
    └─sda1            8:1    0    50G  0 part /mnt
    sdb               8:16   0     8G  0 disk
    └─sdb1            8:17   0     7G  0 part /mnt/home
    └─sdb2            8:18   0  1022M  0 part /mnt/efi

4. Change-root into the new system:

    $ arch-chroot /mnt/

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1. Update pacman mirrors:

    $ sudo reflector --verbose --country "United States" --protocol https --sort rate --age 6 --save /etc/pacman.d/mirrorlist

2. Use pacman to update or fix package issues:

    Refresh package databases and ensure keyring is up-to-date: https://www.reddit.com/r/archlinux/comments/1leg9ds/why_doesnt_pacman_just_install_archlinuxkeyring/
    $ pacman -Syy --noconfirm --needed archlinux-keyring    <-- Pacman 7.1.0+ should auto-refresh keys so in theory this is unnecessary: https://www.reddit.com/r/archlinux/comments/1olm2hc/pacman710_released

    $ pacman -Syyu    <-- If this gives errors then you might need to do step 3 first.

    $ pacman -S <install missing packages to fix issue>

    $ pacman -Qkk    <-- Check integrity of packages.

3. Reinstalling kernel:

    Untested new way since udev was merged into systemd:

    1. $ pacman -S systemd linux mkinitcpio
    2. $ mkinitcpio -P    <-- Might be able to skip if step 1 performs this via the kernel's pacman hook.

    Or old udev notes    <-- Might be useful if repairing an outdated arch.

    SOURCE: https://bbs.archlinux.org/viewtopic.php?id=148037
    1. $ pacman -S udev linux mkinitcpio
    2. $ mkinitcpio -P    <-- Might be able to skip if step 1 performs this via the kernel's pacman hook.

4. Reinstalling bootloader:    <-- I use grub btw.

    NOTE: This might be needed to recreate the NVRAM entry for Arch so the BIOS knows what partition will boot Linux.

    1. Installation:

        WARNING: I use the new /efi path. If using /boot/efi then use this --efi-directory=/boot/efi

        $ grub-install --target=x86_64-efi --efi-directory=/efi --bootloader-id=Arch --removable

    2. Generate the main configuration file:

        NOTE: If you're experiencing black screen nvidia driver issues then you might need to first edit GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub

        $ grub-mkconfig -o /boot/grub/grub.cfg    <-- Some distros have a $ update-grub script that does this.

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1. Exiting chroot and shutting down machine:

    $ exit or Ctrl+d

    $ umount -lR /mnt/    <-- Unmount all partitions.

    $ shutdown now    <-- NOTE: On a non-root account use [$ sudo shutdown now].

    Remove installation media.

2. If repairing a virtual machine:

    1. Settings > Storage:

        Controller: IDE

            Eject iso if still mounted.

    2. Enable EFI boot:

        Settings > System:

            [x] Enable EFI (special OSes only)