[FE training-materials-updates] Android: README explaining how to install U-Boot

[Alexandre Belloni]

Repository : git://git.free-electrons.com/training-materials.git

On branch  : master
Link       : http://git.free-electrons.com/training-materials/commit/?id=487f500bdde237dcccef119c403a2c20922c7098

>---------------------------------------------------------------

commit 487f500bdde237dcccef119c403a2c20922c7098
Author: Chris Simmonds <chris at 2net.co.uk>
Date:   Thu Mar 27 17:51:15 2014 +0100

    Android: README explaining how to install U-Boot
    
    The README file explains how to install U-Boot with fastboot
    support and use fastboot to install images into eMMC flash.
    Add a reference to the README from the New Board lab notes
    
    Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>


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487f500bdde237dcccef119c403a2c20922c7098
 lab-data/android/bootloader/README.txt |  134 ++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

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+======================================================================
+Install U-Boot on the BeagleBone Black's internal flash storage (eMMC)
+======================================================================
+
+We use a version of U-Boot that supports the Android fastboot protocol
+and can read Android boot image files
+
+Tested on the following board revisions:
+- Rev A5C
+
+Make a bootable micro-SD card
+-----------------------------
+
+We are going to prepare a bootable micro-SD card that will allow us to
+use fastboot comands to write to the internal eMMC memory.
+
+Take a micro-SD card and connect it to your PC:
+- Either using a direct SD slot if available.
+  In this case, the card should be seen as '/dev/mmcblk0' by
+  your computer (check the 'dmesg' command output).
+- Either using a memory card reader.
+  In this case, the card should be seen as '/dev/sdb', or '/dev/sdc',
+  etc.
+
+Now, run the mount command to check for mounted SD card
+partitions. Umount them with a command such as
+'sudo umount /dev/mmcblk0p1' or 'sudo umount /dev/sdb1',
+depending on how the system sees the media card device.
+
+Now type the below command to partition the micro-SD card
+(we assume that the card is seen as '/dev/mmcblk0'):
+
+sudo sfdisk --in-order --Linux --unit M /dev/mmcblk0 << EOF
+1,48,0xE,*
+,,,-
+EOF
+
+Now, format the first partition in FAT format:
+
+sudo mkfs.vfat -F 16 /dev/mmcblk0p1 -n boot
+
+Remove the card and insert it again. It should automatically be
+mounted '/media/boot' (or '/media/<user>/boot' if you are using Ubuntu
+12.10 or later).
+
+Now, copy the files to this partition:
+
+cp MLO u-boot.img /media/boot/
+
+Now, unmount '/media/boot' and you are done!
+
+Using your bootable micro-SD card
+---------------------------------
+
+WARNING: this will erase everything in the eMMC storage. If you want
+to restore the factory default installation later, follow the
+instructions here: http://elinux.org/Beagleboard:Updating_The_Software
+
+As well as the BeagleBone and micro SD card, you will need a serial to
+USB cable and it is recommended that you use an external power supply
+because the current used whe writing to the eMMC chip may exceed that
+supplied by a typical USB port.
+
+With no power on the BeagleBone board, insert the micro-SD card in the
+corresponding slot.
+
+Plug in the serial cable. A serial port should appear on your PC as
+/dev/ttyUSB0. Start a suitable terminal program such as picocom and
+attach to the port:
+
+picocom -b 115200 /dev/ttyUSB0
+
+Now, press and hold the 'Boot Switch' button on the Beaglebone (it is
+the only one near the USB host slot), power up the board using the
+external 5V power connector and release the button after about 5
+seconds.
+
+You should see a U-Boot prompt on the serial console
+
+U-Boot#
+
+Type "fastboot" to enable the fastboot protocol on U-Boot. Make sure
+that you have plugged in the USB cable between the micro USB port on
+the BeagleBone and the PC. On the PC, check that the BeagleBone is
+detected:
+
+fastboot devices
+90:59:af:5e:94:81	fastboot
+
+Change into the directory containing MLO and u-boot.bin. Use fastboot
+to flash them into the eMMC chip on the BeagleBone:
+
+$ fastboot oem format
+$ fastboot flash spl MLO
+$ fastboot flash bootloader u-boot.img
+
+Power off the board, remove the SD card and check that it boots from
+eMMC with the new U-Boot installed.
+
+Now you can flash Android images into the eMMC partitions using
+commands such as
+
+fastboot flash userdata
+fastboot flash cache
+fastboot flashall
+
+===============================
+How the binaries where compiled
+===============================
+
+Compiling U-Boot
+----------------
+
+Get a copy of the source code:
+
+git clone git://git.free-electrons.com/android/beagleboneblack/u-boot
+cd u-boot
+git checkout am335x-v2013.01.01-bbb-fb
+
+Since you are likely to be building this along with AOSP, we are using
+the Android cross compiler from prebuilts, but probably any recent arm
+eabi toolchain will do. If you have sourced build/envsetup.sh and
+selected the lunch combo the path will be set up already. If not set
+it now, where ${AOSP} is the place where you installed your AOSP. It
+was tested with Android 4.3, which has gcc version 4.7:
+
+PATH=${AOSP}/prebuilts/gcc/linux-x86/arm/arm-eabi-4.7/bin:$PATH
+
+Then configure and build:
+$ make CROSS_COMPILE=arm-eabi- distclean
+$ make CROSS_COMPILE=arm-eabi- am335x_evm_config
+$ make CROSS_COMPILE=arm-eabi- 
+
+This produces the two files: MLO and u-boot.img.