My customization recipe for SystemRescue:

sysrescue-customize.sh is required to apply these customizations

This recipe adds the following to the custom ISO:

• It adds an "authorized_keys" file in /root/.ssh/ so I can connect to the custom SystemRescue via SSH and authenticate with my SSH keys
• It adds an "id_ed25519" file in /root/.ssh/ so I can connect to other devices through ssh
• It adds a custom autorun script to open inbound and outbound connections on port 22 for ssh connections
• It adds a settings yaml file which overrides the default settings so the custom SystemRescue starts with my own preferences, such as a spanish keyboard, it copies the system into RAM (so the boot device can be removed), and it automatically starts the graphical environment.

Please note the ".squashfs-pseudo" file is important to enforce correct permissions and ownership on the /root directory and its contents. You should update this file is you add more custom files into the system through the SRM.

Please read the official documentation for more details: https://www.system-rescue.org/scripts/sysrescue-customize/