What is the boot kernel option (casper) to change the size of the ram root file system when booting from livecd. I want to be able to install few packages to work with, w/o really installing the system.
You can't control the writable portion of the usb by a boot kernel option. What you need to do is to expand the persistent file system on the usb drive, the
casper-rw file. See this tutorial for a step by step explanaition.