Create CROSS-COMPILING

CROSS-COMPILING

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+# CROSS-COMPILING
+Installing a distro for ARM. The distro is CRUX, the target is an Odroid C2.
+
+
+## TOC
+1. [CROSS COMPILATION TOOLS](#cross-compilation-tools)  
+2. [PARTITIONING](#partitioning)  
+3. [BOOTLOADER](#bootloader)  
+4. [BOOT PARTITION](#boot-partition)  
+5. [ROOT PARTITION](#root-partition)  
+6. [COMPILING](#compiling)  
+
+
+## CROSS COMPILATION TOOLS
+Installing cross GCC compilation tools (for the X86 machine, not target ARM). Includes binutils.
+
+* OPTION 1: from repository (Devuan example)  
+`sudo apt-get install gcc-arm-none-eabi`
+
+* OPTION 2: proportioned by odroid  
+```
+wget http://odroid.in/guides/ubuntu-lfs/arm-unknown-linux-gnueabi.tar.xz
+tar -Jxf arm-unknown-linux-gnueabi.tar.xz
+```  
+
+Name of "_CROSS_COMPILE_" variable will change depending on the choosen option. This guide assumes from repository and therefore will equal to "_CROSS\_COMPILE=arm-none-eabi-_"
+
+
+## PARTITIONING
+* clear the section for the bootloader  
+`dd if=/dev/zero of=/dev/mmcblk0 bs=1M count=8`  
+* enter fdisk  
+`fdisk /dev/mmcblk0`  
+* help  
+`m`  
+* create new MBR partition table  
+`o`  
+* create boot partition  
+`n`  
+* assign start of boot partition at the end of the bootloader space  
+`3073`  
+* assign end of boot partition  
+`+128M`  
+* create root partition  
+`n`  
+* press enter twice to use the rest of the disk  
+Make 
+`mkfs.<ROOT_FILESYSTEM> /dev/sda2`  
+* Make boot filesystem according to supported bootloader or just "_mkfs.vfat_" if on UEFI.  
+`mkfs.<BOOTLOADER_FILESYSTEM> /dev/sda1`  
+
+
+## BOOTLOADER
+Minimum 3072 bytes free at the start of the drive and before the boot partition.
+
+* VERSION 1: compile
+```
+git clone https://github.com/hardkernel/u-boot.git -b odroidc2-v2015.01
+cd u-boot
+make ARCH=arm64 CROSS_COMPILE=arm-none-eabi- odroidc2_defconfig
+make -j4
+cd boot
+```
+
+* VERSION 2: download and extract the binary
+```
+wget http://odroid.in/guides/ubuntu-lfs/boot.tar.gz # http://dn.odroid.com/S905/BootLoader/ODROID-C2/c2_boot_release_ubuntu.tar.gz
+tar -zxvf boot.tar.xz
+cd boot
+```
+
+* flash bootloader
+```
+chmod +x sd_fusing.sh
+./sd_fusing.sh /dev/sdX
+```
+* notice the target is the device NOT any partition
+* set resolution by editing file root/boot/boot.ini
+* might want to comment-out the display-autodetect option
+
+
+## BOOT PARTITION
+Must be FAT32 and 64 MB minimum.
+
+* cloning kernel repo to destination "odroidc2-kernel-folder"
+`git clone --depth 1 --single-branch https://github.com/hardkernel/linux.git --branch odroidc2-v3.16.y odroidc2-kernel-folder`
+* enter destination folder
+`cd odroidc2-kernel-folder`
+
+* OPTION 1: making kernel config
+`make ARCH=arm64 CROSS_COMPILE=arm-none-eabi- odroidc2_defconfig`
+
+* OPTION 2: making kernel config
+```
+export ARCH=arm64
+export CROSS_COMPILE=arm-none-eabi-
+make odroidc2_defconfig
+```
+
+* Refine configuration
+`make menuconfig`
+
+
+## COMPILING
+* Compiling devicetree blobs to destination "INSTALL_DTBS_PATH=/mnt/boot/dtbs/meson64_odroidc2.dtb"
+`make -j 4 ARCH=arm64 CROSS_COMPILE=arm-none-eabi- INSTALL_DTBS_PATH=/mnt/boot/dtbs/ dtbs`
+* Compiling kernel to destination "INSTALL_PATH=/mnt/boot/Image"
+`make -j 4 ARCH=arm64 CROSS_COMPILE=arm-none-eabi- INSTALL_PATH=/mnt/boot/ Image`
+* Compiling the modules to destination "INSTALL_MOD_PATH=/mnt/"
+`make -j 4 ARCH=arm64 CROSS_COMPILE=arm-none-eabi- INSTALL_MOD_PATH=/mnt/ modules_install`
+* Compiling firmware to destination "INSTALL_FW_PATH=/mnt/lib/firmware/"
+`make -j 4 ARCH=arm64 CROSS_COMPILE=arm-none-eabi- INSTALL_FW_PATH=/mnt/lib/firmware/ firmware_install`
+* Compiling kernel C headers to destination "INSTALL_HDR_PATH=/mnt/usr/"
+`make -j 4 ARCH=arm64 CROSS_COMPILE=arm-none-eabi- INSTALL_HDR_PATH=/mnt/usr/ headers_install`
+
+
+## ROOT PARTITION
+Can be the rest of the disk.
+
+* Download CRUX image
+`wget -c http://resources.crux-arm.nu/files/devel-test/3.3/crux-arm-rootfs-3.3-64b-RC2.tar.xz`