How to: Fast boot time for Raspberry Pi

Step 1: Edit the /Boot/Config.txt File

sudo nano /boot/config.txt

Add the following lines at the bottom of the config.txt file.

disable_splash=1: Disables the rainbow splash screen that appears on booting your Raspberry Pi OS.
dtoverlay=disable-bt: Disables Bluetooth .
boot_delay=0: By default, this value is set to 1second if not specified.
initial_turbo=30: Turbo for the first 30 seconds.

Step 2: Overclock the Raspberry Pi

sudo nano /boot/config.txt

over_voltage=6
arm_freq=2140
gpu_freq=750

Step 3. Reduce Kernel Verbose on Boot

Omit any lines of codes running down the monitor (if connected). We don’t need the kernel outputting whatever it is doing for a headless Pi.

sudo nano /boot/cmdline.txt

console=serial0,115200 console=tty1 root=PARTUUID=71a81b7a-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet plymouth.ignore-serial-consoles

Step 4: Use Systemd-Analyze Blame

systemd-analyze blame

Based on the output you get, belows are some of the services that you can disable.

sudo systemctl disable avahi-daemon.service
sudo systemctl disable triggerhappy.service
sudo systemctl disable dhcpcd.service
sudo systemctl disable networking.service
sudo systemctl disable ntp.service
sudo systemctl disable dphys-swapfile.service
sudo systemctl disable keyboard-setup.service
sudo systemctl disable hciuart.service
sudo systemctl disable raspi-config.service
sudo systemctl disable apt-daily.service
sudo systemctl disable wifi-country.service