Android eMMC Booting - OMAPpedia

Android eMMC Booting - OMAPpedia:

eMMC binaries

This is the efi partition table as exists on the emmc

Sector#    Size Name     256     128K xloader     512     256K bootloader    2048       8M recovery                                                         18432       8M boot                                                             34816     512M system                                                         1083392     256M cache                                                          1607680     512M userdata                                                       2656256    2183M media 

[edit]Creating the GPT table

On Target

1. Connect a USB cable to the OTG port on your platform
2. Boot your platform up with a stock u-boot and MLO
3. Once you platform is booted you will see the following:

Fastboot entered... 

On Host Machine

locate fastboot in you android filesystem

cd $mydroid/out/host/linux-x86/bin/fastboot 

Search for fastboot devices

fastboot devices 

Create GPT table on eMMC/SD card

fastboot oem format 

From the android build these are the binaries that go into each partition:

 Sector#    Size Name            Binary     256     128K xloader         MLO     512     256K bootloader      u-boot.bin    2048       8M recovery        recovery.img                                                       18432       8M boot            boot.img                                     34816     512M system          system.img                                       1083392     256M cache           cache.img                                     1607680     512M userdata        userdata.img                                      2656256    2183M media           none 

File locations

• MLO --> x-loader/MLO
• u-boot --> u-boot/u-boot.bin
• boot.img --> need to create using zImage + ramdisk.img
• recovery.img ---> need to create using zImage + ramdisk-recovery.img
• system.img --> $mydroid/out/target/product//system.img
• cache.img -->
• userdata.img --> $mydroid/out/target/product//userdata.img

All these partitions can be flashed with the given binary using fastboot.

 fastboot flash   

Example flashing of all partitions

 fastboot flash xloader     MLO  fastboot flash bootloader  u-boot.bin  fastboot flash recovery    recovery.img  fastboot flash boot        boot.img  fastboot flash system      system.img  fastboot flash cache       cache.img  fastboot flash userdata    userdata.img 

[edit]Modifying .IMG Files

Typically when you want to modify any of the partitions, you would need to unzip-modify-rezip and then fastboot flash.

Following section talks about how to do that for each partition

BOOT.IMG

 boot.img = zImage + ramdisk.img  zImage = kernel image  ramdisk.img = out/target/product/blaze/root/  %./out/host/linux-x86/bin/mkbootimg   --kernel zImage   --ramdisk ramdisk.img   --base 0x80000000   --cmdline "console=ttyO2,115200n8 mem=456M@0x80000000 mem=512M@0xA0000000 init=/init vram=10M omapfb.vram=0:4M androidboot.console=ttyO2"   --board omap4   -o boot.img.new  Output: boot.img.new  **Note: bootarg is passed to kernel via --cmdline option above 

To "just" boot boot.img (before flashing) you can use:

%fastboot boot boot.img 

RAMDISK.IMG

 %mkdir root  %cd root  %gunzip -c ../ramdisk.img | cpio -i    %./out/host/linux-x86/bin/mkbootfs root/ | ./out/host/linux-x86/bin/minigzip >ramdisk.img.new  #output: ramdisk.img.new  ** Note: any init.rc changes will need to use this method 

RECOVERY.IMG

Is just like boot.img.  recovery.img = zImage + ramdisk-recovery.img *Follow the same steps as boot.img for packing/unpacking 

SYSTEM.IMG

 #uncompress  %./out/host/linux-x86/bin/simg2img system.img system.img.raw  #mount to directory mnt-point/  %mkdir mnt-point  %sudo mount -t ext4 -o loop system.img.raw mnt-point/  #modify any .so or apk in the mnt-point/ directory  #rezip  %sudo out/host/linux-x86/bin/make_ext4fs -s -l 512M -a system system.img.new mnt-point/  %sudo umount mnt-point/  Output: system.img.new 

Instead of having to reflash the whole big system.img, one can selective update any binary in /system folder on running target

%adb remount %adb push   Eg:  %adb remount %adb push out/target/product/blaze/obj/lib/overlay.omap4.so /system/lib/hw/overlay.omap4.so %adb sync 

USERDATA.IMG

 #uncompress  %./out/host/linux-x86/bin/simg2img userdata.img userdata.img.raw  #mount to directory mnt-point/  %mkdir mnt-point  %sudo mount -t ext4 -o loop userdata.img.raw mnt-point/  #modify any .so or apk in the mnt-point/ directory  #rezip  #%sudo ./out/host/linux-x86/bin/make_ext4fs -s -l 512M -a userdata userdata.img.new mnt/  # Above command won't work on GB/HC. For GB/HC, please use the following updated command  %sudo ./out/host/linux-x86/bin/make_ext4fs -s -l 512M -a data userdata.img.new mnt/  %sudo umount mnt-point/  Output: userdata.img.new 

CACHE.IMG

 #This is empty ext4 fs image  %mkdir mnt-point/  %sudo ./make_ext4fs -s -l 256M -a cache cache.img mnt-point/  Output: cache.img 

[edit]TI Android build setup

Copy kernel zImage, u-boot.bin and MLO for your board in folder device/ti/blaze/boot/.

Rename as:

 %mv MLO MLO_es2.2_emu   or   %mv MLO MLO_es2.2_gp   (based on your board being GP or EMU) 

Next start standard android build and all img files are generated in:

out/target/product/blaze/*.img 

A script is introduced in TI Android release to make this flashing process easier: device/ti/blaze/boot/fastboot.sh

Usage: cd device/ti/blaze/boot/ %fastboot.sh --emu or %fastboot.sh --gp 

Running this script will flash whole android system on your board.

'via Blog this'