Reset the root Password

1. Change the default user to root via command line

# Ubuntu (20.04)
ubuntu2004 config --default-user root

# Debian
debian config --default-user root

# Kali
kali config --default-user root

2. Set the regular user's password

# If you forget the username
ls /home

passwd <USERNAME>

3. Reset the default user via command line

# Ubuntu (20.04)
ubuntu2004 config --default-user <USERNAME>

# Debian
debian config --default-user <USERNAME>

# Kali
kali config --default-user <USERNAME>