--- a/com.cfg	Thu Jul 11 21:57:11 2013 +0200
+++ b/com.cfg	Thu Jul 11 23:25:42 2013 +0200
@@ -140,7 +140,9 @@
 d-i	preseed/include/checksum	string	
 d-i	preseed/include_command	string	
 d-i	preseed/interactive	boolean	false
-d-i	preseed/late_command	string	in-target perl -i.bak -ne 'print unless /^deb cdrom:/' /etc/apt/sources.list
+d-i	preseed/late_command	string	in-target \
+    perl -i.bak -ne 'print unless /^deb cdrom:/' /etc/apt/sources.list; \
+    apt-get update && apt-get safe-upgrade
 d-i	preseed/load_error	error	
 d-i	preseed/retrieve_error	error	
 d-i	preseed/run	string