If no shell was requested via Ctrl-B, exit immediately if boot fails.

src/core/main.c

 	initialise();
 	startup();
 
-	/* Try autobooting if we're not going straight to the shell */
-	if ( ! shell_banner() ) {
+	if ( shell_banner() )
+		shell();
+	else
 		autoboot();
-	}
 	
-	/* Autobooting failed or the user wanted the shell */
-	shell();
-
 	shutdown();
 
 	return 0;