pacman -Qs mkinitcpio
local/hwdetect 2022.04-2
Hardware detection script with loading modules and mkinitcpio.conf
local/mkinitcpio 31-3
Modular initramfs image creation utility
local/mkinitcpio-busybox 1.35.0-1
Base initramfs tools
local/mkinitcpio-nfs-utils 0.3-7
ipconfig and nfsmount tools for NFS root support in mkinitcpio
yea should not be empty… it should look like this:
# mkinitcpio preset file for the 'linux' package
ALL_config="/etc/mkinitcpio.conf"
ALL_kver="/boot/vmlinuz-linux"
PRESETS=('default' 'fallback')
#default_config="/etc/mkinitcpio.conf"
default_image="/boot/initramfs-linux.img"
#default_options=""
#fallback_config="/etc/mkinitcpio.conf"
fallback_image="/boot/initramfs-linux-fallback.img"
fallback_options="-S autodetect"
/etc/mkinitcpio.d/linux.preset
You can try adding it back into the file…
as package is up to date,
sudo nano /etc/mkinitcpio.d/linux.preset
Ctrl+O & Ctrl+X
should I edit & paste them?
# mkinitcpio preset file for the 'linux' package
ALL_config="/etc/mkinitcpio.conf"
ALL_kver="/boot/vmlinuz-linux"
PRESETS=('default' 'fallback')
#default_config="/etc/mkinitcpio.conf"
default_image="/boot/initramfs-linux.img"
#default_options=""
#fallback_config="/etc/mkinitcpio.conf"
fallback_image="/boot/initramfs-linux-fallback.img"
fallback_options="-S autodetect"
yes should work if this is the only issue. 
You will see if it works directly when retry running mkinitcpio -P
mkinitcpio -P
==> Building image from preset: /etc/mkinitcpio.d/linux.preset: 'default'
-> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux.img
==> Starting build: 5.19.7-arch1-1
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [autodetect]
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: xhci_pci
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
==> WARNING: consolefont: no font found in configuration
-> Running build hook: [resume]
-> Running build hook: [filesystems]
-> Running build hook: [fsck]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: /boot/initramfs-linux.img
==> Image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux.preset: 'fallback'
-> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux-fallback.img -S autodetect
==> Starting build: 5.19.7-arch1-1
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: qed
==> WARNING: Possibly missing firmware for module: wd719x
==> WARNING: Possibly missing firmware for module: qla1280
==> WARNING: Possibly missing firmware for module: qla2xxx
==> WARNING: Possibly missing firmware for module: aic94xx
==> WARNING: Possibly missing firmware for module: bfa
==> WARNING: Possibly missing firmware for module: xhci_pci
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
==> WARNING: consolefont: no font found in configuration
-> Running build hook: [resume]
-> Running build hook: [filesystems]
-> Running build hook: [fsck]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: /boot/initramfs-linux-fallback.img
==> Image generation successful
But pacman -U /var/cache/pacman/pkg/mkinitcpio-31-3-any.pkg.tar.zst gives same output
loading packages...
error: '/var/cache/pacman/pkg/mkinitcpio-31-3-any.pkg.tar.zst': could not find or read package
sudo?
same 
Are you on live USB and chrooted into the system?
yes live USB and chrooted into the system. ([root@EndeavourOS /]#)
Perhaps, it could be wise to make a backup of all the files you don’t want to loose from there, (and possibly ponder a re-install afterwards)?
pacman -Syu linux
:: Synchronizing package databases...
core is up to date
extra is up to date
community is up to date
multilib is up to date
endeavouros is up to date
home_ungoogled_chromium_Arch 1951.0 B 253 B/s 00:08 [--------------------------------] 100%
warning: linux-5.19.7.arch1-1 is up to date -- reinstalling
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
Package (2) Old Version New Version Net Change Download Size
extra/ffmpeg 2:5.1.1-1 2:5.1.1-2 0.00 MiB 11.10 MiB
core/linux 5.19.7.arch1-1 5.19.7.arch1-1 0.00 MiB
Total Download Size: 11.10 MiB
Total Installed Size: 214.90 MiB
Net Upgrade Size: 0.00 MiB
:: Proceed with installation? [Y/n] Y
:: Retrieving packages...
ffmpeg-2:5.1.1-2-x86_64 11.1 MiB 1501 KiB/s 00:08 [--------------------------------] 100%
(2/2) checking keys in keyring [--------------------------------] 100%
(2/2) checking package integrity [--------------------------------] 100%
(2/2) loading package files [--------------------------------] 100%
(2/2) checking for file conflicts [--------------------------------] 100%
:: Processing package changes...
(1/2) reinstalling linux [--------------------------------] 100%
(2/2) upgrading ffmpeg [--------------------------------] 100%
:: Running post-transaction hooks...
(1/5) Arming ConditionNeedsUpdate...
(2/5) Updating module dependencies...
depmod: ERROR: failed to load symbols from /lib/modules/5.19.7-arch1-1/updates/dkms/8192eu.ko.zst: Invalid argument
(3/5) Updating linux initcpios...
==> Building image from preset: /etc/mkinitcpio.d/linux.preset: 'default'
-> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux.img
==> Starting build: 5.19.7-arch1-1
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [autodetect]
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: xhci_pci
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
==> WARNING: consolefont: no font found in configuration
-> Running build hook: [resume]
-> Running build hook: [filesystems]
-> Running build hook: [fsck]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: /boot/initramfs-linux.img
==> Image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux.preset: 'fallback'
-> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux-fallback.img -S autodetect
==> Starting build: 5.19.7-arch1-1
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: qed
==> WARNING: Possibly missing firmware for module: wd719x
==> WARNING: Possibly missing firmware for module: qla1280
==> WARNING: Possibly missing firmware for module: qla2xxx
==> WARNING: Possibly missing firmware for module: aic94xx
==> WARNING: Possibly missing firmware for module: bfa
==> WARNING: Possibly missing firmware for module: xhci_pci
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
==> WARNING: consolefont: no font found in configuration
-> Running build hook: [resume]
-> Running build hook: [filesystems]
-> Running build hook: [fsck]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: /boot/initramfs-linux-fallback.img
==> Image generation successful
(4/5) Check if user should be informed about rebooting after certain system package upgrades.
==> INFO: Reboot is recommended due to the upgrade of core system package(s).
(5/5) Checking which packages need to be rebuilt
This time no errors, IDK if that already fixed the issue.
At any rate, do a grub-update, before you try a reboot:
sudo grub-mkconfig -o /boot/grub/grub.cfg
Perhaps, it could be wise to make a backup of all the files you don’t want to loose from there, (and possibly ponder a re-install afterwards)?
Yes but that doesn’t fix the issue & I don’t know how I got here as installed EOS recently i.e. nothing much changed. So if by mistake happens in future I don’t wanna reinstall the OS again. 
Maybe it didn’t really freeze, but only was slow before you decided to restart (early)?
Also, a hardware-issue could be involved?
sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found theme: /boot/grub/themes/EndeavourOS/theme.txt
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/intel-ucode.img /boot/initramfs-linux.img
Found fallback initrd image(s) in /boot: intel-ucode.img initramfs-linux-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
ERROR: mkdir /var/lock/dmraid
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
Adding boot menu entry for UEFI Firmware Settings ...
done
Some errors here as well 
That probably means /dev/sdb1 isn’t mounted.
Edit:
The os-prober script from grub can be executed again, when you rebooted to a working system.
thats totally fine …
only was slow before you decided to restart (early)
Yeah could be, should never restart early. Never experienced such situation before.
So, try a reboot, and we’ll be here waiting for you.
When I type reboot it says Running in chroot, ignoring request. which also confirms I’m in chroot mode.
Restarting… 