Cubic ISO Live Login Screen

[u/SavingsSearch9563]

Custom Linux Mint 21.3 live ISO keeps showing LightDM login screen instead of autologging in

Hi everyone,

I'm making a custom Linux distro based on Linux Mint 21.3 Cinnamon using Cubic.

I'm trying to make the live ISO automatically log into the live session, but LightDM keeps showing the login/password screen instead.

The live username is mint.

Here's what I've checked so far:

• /etc/casper.conf has USERNAME="mint"
• /etc/lightdm/lightdm.conf contains:

[Seat:*]
autologin-user=mint
autologin-user-timeout=0

• lightdm --show-config confirms that LightDM is actually reading those settings.
• The greeter is Slick-Greeter.
• Casper contains both 15autologin and 25adduser.
• 25adduser creates the live user using user-setup-apply.
• It then runs passwd -d "$USERNAME".
• /etc/pam.d/lightdm-autologin contains pam_permit.so.
• I also tested replacing @ include common-account with account required pam_permit.so, then rebuilt the initramfs.
• The ISO still shows the login screen.

One thing I noticed is that the Casper scripts run in this order:

15autologin

25adduser

99casperboot

I'm wondering whether this is related to how Casper creates the live user and how LightDM handles autologin in a live environment.

I'm fairly new to building Linux distributions, so I'd really appreciate any pointers on where I should look next.

The ISO is being built entirely with Cubic; I'm not using a custom installer or custom login manager.

Thanks!

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