[Xiaomi Mi 4C] ketut.kumajaya:
I'm writing this incomplete instruction for my friend [MENTION=3813099]emfox[/MENTION] based on the instruction I used to reconstruct Redmi 2 kernel source http://xdaforums.com/android/software-hacking/how-to-convert-qualcomms-dtb-to-dts-t3221223 Unfortunately I couldn't finish this instruction without Mi 4c device. This is just a quick look, short information, to check the possibility to reconstruct an open source kernel based on CAF project. It's will be hard but not impossible.

1. Clone MSM8992 vanilla kernel source, LA.BF64.1.2.2-02940-8x92.0 release for Marshmallow 6.0.1 (release LA.BF64.1.2.1.c1-05410-8x92.0 branch LA.BF64.1.2.1.c1_rb1.38 for Lollipop 5.1.1) https://www.codeaurora.org/cgit/quic/la/kernel/msm-3.10/?h=LA.BF64.1.2.2_rb4.22

git clone git://codeaurora.org/quic/la/kernel/msm-3.10 -b LA.BF64.1.2.2_rb4.22

2. Stock 4c kernel was compiled without CONFIG_IKCONFIG, vanilla kernel config libra_defconfig attached

3. Attached 3 dts file from stock kernel, msm8992-mtp-0xc.dts seem compatible to emfox device (qcom,board-id = <0xc 0x0>; )

4. Attached a vanilla dts file for MSM8992 MTP msm8992-mtp.dts as a result of LA.BF64.1.2.2_rb4.22 built

You can compare msm8992-mtp-0xc.dts to msm8992-mtp.dts using a diff tool (i.e. Kompare app) and start creating device tree source for Mi 4c: msm8992-mtp-libra.dts, msm8992-mtp-libra.dtsi, batterydata-itech-3020mah.dtsi, dsi-panel-sharp-rsp61322-1080p-video.dtsi, dsi-panel-auo-nt35596-1080p-video.dtsi, dsi-panel-lgd-nt35596-1080p-video.dtsi, dsi-panel-sharp-nt35595-1080p-video.dtsi, dsi-panel-jdi-nt35595-1080p-video.dtsi, msm8992-camera-sensor-mtp-libra.dtsi, etc. You can use https://github.com/kumajaya/android...mmit/3de4f3564a82f44049a8664d4383c6d3ed43cb47 as a reference. Mi 4c based on same board platform as LG G4 or Nexus 5X. Good luck!

How to build kernel outside Android source tree:

I assume your home directory is /home/user, kernel source inside /home/user/android/libra/kernel, Android source tree inside /home/user/android/system-13.0

1. Create an environtment text file, save it as /home/user/android/build-arm64.env (change CROSS_COMPILE to point to your toolchain):

export CROSS_COMPILE='/home/user/android/system-13.0/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android-'
export LDFLAGS=''
export CFLAGS=''
export SUBARCH=arm64
export ARCH=arm64

2. Import environtment file above, create a build directory outside the kernel source tree (to keep the kernel source clean):

$ cd /home/user/android/libra/kernel
$ source /home/user/android/build-arm64.env
$ mkdir -p /home/user/android/libra/kernel-out
$ make O=/home/user/android/libra/kernel-out mrproper

3. Import the kernel config file, change the kernel configuration (if needed) and start the building process:

$ make O=/home/user/android/libra/kernel-out libra_defconfig
$ make O=/home/user/android/libra/kernel-out menuconfig
$ make O=/home/user/android/libra/kernel-out

4. Copy the resulting kernel and modules (if available) to a binary directory:

$ mkdir -p /home/user/android/libra/kernel-bin
$ mkdir -p /home/user/android/libra/kernel-bin/modules
$ cp /home/user/android/libra/kernel-out/arch/arm64/boot/Image /home/user/android/libra/kernel-bin/
$ find /home/user/android/libra/kernel-out/ -type f -name *.ko -exec cp {} /home/user/android/libra/kernel-bin/modules/ \;

Creating a boot image:

Remember, this is incomplete guide :D