TipsAndTricksPrebootUpdateEtc < Training

%SECTION0{name=TipsAndTricks}% U-Boot Tips and Tricks: preboot, update, etc.

   preboot: This variable can be used to run specific code before the normal startup
     (i.e. CONFIG_BOOTDELAY loop, autostart or interactive mode) begins.
     This is especially useful when its contents are generated automatically, i.e. by checking for keypresses, etc.

   update: [todo: explain update procedures using U-Boot]

   Loading&nbsp;Compressed&nbsp;Images: Sometimes you may want to store
      some data in compressed format (for example to save flash memory), while
      your application needs the data in uncompressed form. You can trick U-Boot
      to do this uncompressing like this:
      <br><br>
      Generate a compressed U-Boot image of type "standalone" (="mkimage ... -T
      standalone -C gzip ..."=) and make sure that the envrionment variable
      ==autostart== is set to ==no== (i. e. enter
      ="setenv autostart no;saveenv"=). If you then use "bootm" for such an
      image, U-Boot will uncompress the contents of the image and store it at the
      "load address" (="-a"= option for mkimage), but not attempt to start it yet.
      If the image contains executable code, you can omit the setting of
      "autostart", and U-Boot will automagically start the image by jumping
      to the entry point address ("-e" option for mkimage).

11. The powerful U-Boot command line interface		1. Embedded Linux Training course		12. Build, configuration of the Linux kernel, more details
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