Do not specify something in the script that would prevent the mounting of file systems onto /a during an initial or upgrade installation. If the JumpStart program cannot mount the file systems onto /a, an error occurs and installation fails.
During the installation, output from the begin script is deposited in /tmp/begin.log. After the installation is completed, the log file is redirected to /var/sadm/system/logs/begin.log.
Ensure that root owns the begin script and that the permissions are set to 644.
You can use custom JumpStart Environment variables in your begin scripts. For a list of environment variables, see Custom JumpStart Environment Variables.
Save begin scripts in the JumpStart directory.