- Grab a USB and download the Arch ISO
- Use balenaEtcher and flash the ISO to the stick
- Boot onto stick
Firstly, check if you have internet real quick ping 8.8.8.8
If not, I would recommend using iwctl, and follow this for Wi-Fi.
Use lsblk or fdisk -l and find your file system mounts, can have a root, home and an EFI, find 'em all.
Mount the system mount /dev/xxx1 /mnt, ... /mnt/home, ... ... /mnt/boot (or ... /mnt/efi)
Chroot into your system arch-chroot /mnt
In case you can't remember whether you originally mounted to /mnt/efi or /mnt/boot, you can double-check your fstab cat /etc/fstab.
Cool, now you have your files safe again, and it's time to be a detective.
Try refreshing keys: pacman-key --refresh-keys
Try re-installing archlinux-keyring: pacman -S archlinux-keyring
If something is really wrong with your keyring you might wanna hard-reset it (back up in-case something goes wrong):
mv /etc/pacman.d/gnupg /.../gnupg_backup
mv /root/.gnupg /.../gnupg_root_backup
gpg --refresh-keys
pacman-key --init
pacman-key --populate
pacman-key --refresh-keys
Check logs for broken packages: /var/log/pacman.log
Closed pacman rudely? Delete /var/lib/pacman/db.lck manually
In some cases the initramfs can become corrupted. Run mkinitcpio -p linux to rebuild it
In case of not being able to find vmlinuz-linux for example, check your /boot /efi and see if it's there.
Keep in mind the default for mkinitcpio is to save under /boot, if you had saved your ESP on /efi when installing, do keep in mind NOT to mount your ESP to /boot when chrooting in, as that would essentially make mkinitcpio save the files to what is effectively mapped to /efi. Check your fstabs for this: cat /etc/fstab. In this case, just mount your ESP to the correct place as in your fstab and re-run building the kernel.