U-Boot

boot.scr

On boot, U-Boot looks for a file called boot.scr which it will try to run. Users can create such a script to do boot time configuration of the board, do low-level testing, or set up the U-Boot environment. A common use case is to do a one-time configuration and reflash of boards to be deployed without microSD cards.

For example, this script flashes a new x-load, U-Boot, and kernel image to an Overo board. If it is mounted on an expansion board with LEDs, the blue one will light up if the script completes successfully or a red one will light up if the script fails. The following files should be loaded on a microSD card (taking care to copy over x-load first):

* x-load-new
* mlo
* u-boot
* u-boot-new
* uimage-new

setenv success 1
setenv loadaddr 0x82000000
setenv ext new
# clear daughter card LEDs (GPIO21 and GPIO22)
mw 48310034 ff9fffff
mw 48310094 00600000

# Two notes:
# 1. FAT file-systems handle letter case strangely---we should use
#    lower-case only
# 2. x-load should be copied first to the microSD card otherwise U-Boot
#    doesn't see it.

if mmc init; then
  echo "Flashing uimage${ext}..."
  nandecc sw
  nand erase
  if fatload mmc 1 ${loadaddr} uimage${ext}; then
     nand write ${loadaddr} 0x00200000 0x00500000
  else
    echo "ERROR: couldn\'t find uimage${ext}..."
    setenv success 0
  fi

  echo "Flashing u-boot${ext}.bin..."
  if fatload mmc 1 ${loadaddr} u-boot${ext}.bin; then
    nand write ${loadaddr} 0x00080000 0x001c0000
  else
    echo "ERROR: couldn\'t find u-boot${ext}.bin..."
    setenv success 0
  fi

  echo "Flashing x-load${ext}..."
  if fatload mmc 1 ${loadaddr} x-load${ext}; then
    nandecc hw
    nand write ${loadaddr} 0x00000000 0x00080000
  else
    echo "ERROR: couldn\'t find x-load${ext}..."
    setenv success 0
  fi
else
  echo "Please insert a microSD and reboot the board"
  setenv success 0
fi

# display error condition
if test $success -eq 1; then
  # SUCCESS: light up LED on GPIO22
  mw 48310090 00400000
  echo "COMPLETED SUCCESSFULLY"
else
  # ERROR: light up LED on GPIO21
  mw 48310090 00200000
  echo "COMPLETED WITH ERRORS"
fi