Fake the GPT once for ARM to determine parameters for U-Boot script

src/scripts/build_gpt.sh

 #!/bin/bash
 #
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
-
 # Load common constants.  This should be the first executable line.
 # The path to common.sh should be relative to your script's location.
 . "$(dirname "$0")/common.sh"
 
 # Load functions and constants for chromeos-install
 . "$(dirname "$0")/chromeos-common.sh"
 
 # Script must be run inside the chroot.
 assert_inside_chroot
 
@@ skipping 78 matching lines @@
 
 STATEFUL_IMG="${IMAGEDIR}/stateful_partition.image"
 if [[ ! -s ${STATEFUL_IMG} ]]; then
   error "Can't find ${STATEFUL_IMG}"
   exit 1
 fi
 
 # We'll need some code to put in the PMBR, for booting on legacy BIOS. Some ARM
 # systems will use a U-Boot script temporarily, but it goes in the same place.
 if [[ "$ARCH" = "arm" ]]; then
-  # U-Boot script copies the kernel into memory, then boots it.
+  # We need to know the location and size of the kernel so we can create the
+  # U-Boot script to point to it. Let's create one fake GPT first which will
+  # set the appropriate environment variables. Then we can create the correct
+  # script and install it for real. A bit awkward, but this is only temporary.
+  echo "Installing fake GPT first, to calculate locations..."
+  install_gpt $OUTDEV $ROOTFS_IMG $KERNEL_IMG $STATEFUL_IMG /dev/zero
+
+  # Create the U-Boot script to copy the kernel into memory and boot it.
   KERNEL_OFFSET=$(printf "0x%08x" ${START_KERN_A})
-  KERNEL_SECS_HEX=$(printf "0x%08x" ${NUM_KERN_BLOCKS})
+  KERNEL_SECS_HEX=$(printf "0x%08x" ${NUM_KERN_SECTORS})
   MBR_SCRIPT="${IMAGEDIR}/mbr_script"
   echo -e "echo\necho ---- ChromeOS Boot ----\necho\n" \
           "mmc read 1 C0008000 $KERNEL_OFFSET $KERNEL_SECS_HEX\n" \
           "bootm C0008000" > ${MBR_SCRIPT}
   MKIMAGE="${FLAGS_board_root}/u-boot/mkimage"
   if [[ -f "$MKIMAGE".gz ]]; then
     sudo gunzip "$MKIMAGE".gz
   fi
   if [[ -x "$MKIMAGE" ]]; then
     MBR_SCRIPT_UIMG="${MBR_SCRIPT}.uimg"
@@ skipping 18 matching lines @@
 # Now populate the partitions.
 echo "Copying stateful partition..."
 dd if=${STATEFUL_IMG} of=${OUTDEV} conv=notrunc bs=512 seek=${START_STATEFUL}
 
 echo "Copying kernel..."
 dd if=${KERNEL_IMG} of=${OUTDEV} conv=notrunc bs=512 seek=${START_KERN_A}
   
 echo "Copying rootfs..."
 dd if=${ROOTFS_IMG} of=${OUTDEV} conv=notrunc bs=512 seek=${START_ROOTFS_A}