-To make a MXS based board bootable, some tools are necessary. The first one is
-the "elftosb" tool distributed by Freescale Semiconductor. The other one is the
-"mxsboot" tool found in U-Boot source tree.
+To make a MXS based board bootable, some tools are necessary. The only
+mandatory tool is the "mxsboot" tool found in U-Boot source tree. The
+tool is built automatically when compiling U-Boot for i.MX23 or i.MX28.
+
+The production of BootStream image is handled via "mkimage", which is
+also part of the U-Boot source tree. The "mkimage" requires OpenSSL
+development libraries to be installed. In case of Debian and derivates,
+this is installed by running:
+
+ $ sudo apt-get install libssl-dev
+
+NOTE: The "elftosb" tool distributed by Freescale Semiconductor is no
+ longer necessary for general use of U-Boot on i.MX23 and i.MX28.
+ The mkimage supports generation of BootStream images encrypted
+ with a zero key, which is the vast majority of use-cases. In
+ case you do need to produce image encrypted with non-zero key
+ or other special features, please use the "elftosb" tool,
+ otherwise continue to section 2). The installation procedure of
+ the "elftosb" is outlined below: