I wanted to download cst-2.3.1.tar.gz. But I can't find the resouce link.
By the following link, I can only download the latest one ("cst-3.1.0.tgz").
i.MX High Assurance Boot Reference Code Signing Tool
https://www.nxp.com/webapp/sps/download/license.jsp?colCode=IMX_CST_TOOL