Release notes for U-Boot updates, May 27, 2006

Added command mmcdet to detect SD card

The mmcdet command does not produce any output, but sets a return value to true if an SD card is present for use in scripts.

Added command not

This command is designed to be used in conjunction with the mmcdet command. It expects a command and parameters as arguments, and performs a logical not on the return result from the parameter. Consider the following example from include/configs/neon.h.
   while not mmcdet ; do 
      cls ; 
      lecho "insert SD card" ; 
      sleep 1 ; 
   done
This command sequence waits until an SD card is detected before continuing.

Added command mmcwp to detect SD card write protect

As with mmcdet, this command does not produce any output, but can be used in scripts like so: 
   if mmcwp ; then 
      lecho "write protected" ; 
   else 
      lecho "not write protected" ; 
   fi

Changed default configuration to use CONFIG_AUTOBOOT_KEYED

This change means that more than a keystroke is necessary to abort the boot.
This is useful when the primary (Full Function) serial port is used to connect to an external device.

The default password is three escape characters.
In order to stop the boot, you must enter these keystrokes.

Added make target for upgrade.scr

The source script file u-boot-1.1.2/upgrade.script is used as a target for an upgrade script.
Note that the U-Boot file name is loaded using a wildcard, to make it easier to update an upgrade SD image, but that this may not work on devices with U-Boot versions older than 1.3 (January 2006).

If you have an older U-Boot image on your device, you'll need to re-generate the upgrade script file using a specific file name.

Look here if you don't know what I'm talking about.