zs5zk,
Welcome to LQ forums.
Open a Terminal (Ctrl + Alt + T), then copy & paste (to avoid typing errors) this command:
Code:
xed admin:///etc/initramfs-tools/initramfs.conf
Press Enter.
In this file change COMPRESS=lz4 to COMPRESS=gzip
Click on Save.
Then use this command:
Code:
sudo update-initramfs -u
Reboot.