initrd configuration

It’s time to prepare initrd part of your boot image.

You need to decide which path you prefer: udev-based initrd or systemd-based one.

If you have no idea, choose the first (Manjaro/Arch default). Hereinafter everything hallmarked with (a) should be considered referring to udev-based initrd setup, and everything with a foregoing (b) literal – referring to systemd-based setup.

Backup your existing mkinitcpio file with a timestamp

# cp /etc/mkinitcpio.conf /etc/mkinitcpio.conf.$(date +%Y%m&d%H%M)

Then edit your /etc/mkinitcpio.conf and replace the line HOOKS=

Either the udev type (a)

HOOKS=(base udev keyboard consolefont autodetect plymouth modconf block plymouth-tpm2-totp tpm2 plymouth-encrypt lvm2 resume filesystems)

Or the systemd type (b)

HOOKS=(base systemd keyboard sd-vconsole autodetect sd-plymouth modconf block sd-plymouth-tpm2-totp sd-encrypt lvm2 filesystems)

For scripting purpose - using sed to edit the file in place - adding the previous hooks for backup purpose

Either udev type (a)

OLD_HOOKS=$(cat /etc/mkinitcpio.conf | grep "^HOOKS=(")
sed -i 's/"${OLD_HOOKS}"/HOOKS=(base udev keyboard consolefont autodetect plymouth modconf block plymouth-tpm2-totp tpm2 plymouth-encrypt lvm2 resume filesystems)/g' /etc/mkinitcpio.conf 
echo "#previous_$OLD_HOOKS" | tee -a /etc/mkinitcpio.conf

Or systemd type (b)

OLD_HOOKS=$(cat /etc/mkinitcpio.conf | grep "^HOOKS=(")
sed -i 's/'"${OLD_HOOKS}"'/HOOKS=(base systemd keyboard sd-vconsole autodetect sd-plymouth modconf block sd-plymouth-tpm2-totp sd-encrypt lvm2 filesystems)/g' /etc/mkinitcpio.conf 
echo "#previous_$OLD_HOOKS" | tee -a /etc/mkinitcpio.conf

Add an entry about your LUKS partition to crypttab (discard is optional)

CRYPT_PART=/dev/nvme0n1p2
echo cryptlvm $(blkid -s UUID -o value $CRYPT_PART) - tpm2-device=/dev/tpmrm0,tpm2-pcrs=0+7+14,nofail,discard,x-initrd.attach | tee -a /etc/crypttab.initramfs

For better (de)compression speed/efficiency ratio consider setting COMPRESSION="zstd" in your /etc/mkinitcpio.conf if not set already.
Note This works only with kernels from 5.10 and onwards

sed -i 's/#COMPRESSION="zstd'/COMPRESSION="zstd"/g' /etc/mkinitcpio.conf

This is not a good time to loose power or ... dang - I have to start over ....

kernel 5.10/5.15 systemd type partial script

CRYPT_PART=/dev/nvme0n1p2
echo cryptlvm $(blkid -s UUID -o value $CRYPT_PART) - tpm2-device=/dev/tpmrm0,tpm2-pcrs=0+7+14,nofail,discard,x-initrd.attach | tee -a /etc/crypttab.initramfs
cp /etc/mkinitcpio.conf /etc/mkinitcpio.conf.$(date +%Y%m&d%H%M)
OLD_HOOKS=$(cat /etc/mkinitcpio.conf | grep "^HOOKS=(")
sed -i 's/'"${OLD_HOOKS}"'/HOOKS=(base systemd keyboard sd-vconsole autodetect sd-plymouth modconf block sd-plymouth-tpm2-totp sd-encrypt lvm2 filesystems)/g' /etc/mkinitcpio.conf 
echo "#previous_$OLD_HOOKS" | tee -a /etc/mkinitcpio.conf
sed -i 's/#COMPRESSION="zstd'/COMPRESSION="zstd"/g' /etc/mkinitcpio.conf