[Xiaomi Mi A1 Guides, News, & Discussion] ManojNairOnline:
The problem with reading the articles on XDA is that eventually you want to try out some of the things described in these pages. I am no exception. After reading the superb article https://xdaforums.com/mi-a1/how-to/guide-build-rom-source-tissot-t3754723 I decided to try my hand at developing the ROM for the Xiaomi MiA1. This is my daily driver and that in itself was a strong reason for motivation.

I tried replicating the steps given in the article on my Dell Inspiron and immediately ran into issues. The basic requirements mentioned are a linux or Mac computer. So to start with I formatted my laptop. Removed windows 10 and installed Ubuntu's latest 18.04 LTS.

I believed I had the next set of requirements for custom ROM development which were

• A basic understanding of Linux based OS specifically Ubuntu.

• Ability to type and use the command line. Write or copy paste commands in the Ubuntu konsole.

• A basic understanding of programming concepts, read and update XML files, understand error messages.

• Fast internet access.

• Steady electricity supply.

• Lots and lots of patience.

This still did not solve my problem. The build would crash repeatedly. Then I read the https://source.android.com/setup/. A whole new set of requirement came up. The article said that ideally the build system should exceed these conditions

• 64 bit environment

• 100 GB of free hard disk space

• 16 GB RAM / swap space.

At home my son was about to buy a new PC and this made his old PC available. I upgrade the RAM and added a new hard disk. Now my hardware configuration was as under :

• Intel i5 processor

• 16 GB RAM

• 1 TB hard disk.

With a new hard disk I had to create a boot-able USB drive. This I achieved with Rufus. My old laptop which again had its Windows 10 installation was used to install Rufus based on the instructions i got from https://rufus.akeo.ie/

The latest version of Ubuntu I downloaded from https://www.ubuntu.com/download/desktop

Setting Ubuntu from scratch for someone used to the world of windows is not exactly easy. I found the tutorial at https://tutorials.ubuntu.com/tutorial/tutorial-install-ubuntu-desktop#0 extremely helpful.

I wrote down the steps I took in reaching the final goal of a Lineage ROM for my Mi A1.

Step 1: Setup Ubuntu - already completed

I chose the default settings as recommended in the setup.

Step 2: Installation of Java Development Kit

Once Ubuntu was up and running I opened a konsole window and typed the following commands

sudo apt-get update
sudo apt-get install openjdk-8-jdk

Ubuntu did all the installing as I looked on.

Step 3: Installing required packages

sudo apt-get install git-core gnupg flex bison gperf build-essential zip curl zlib1g-dev gcc-multilib g++-multilib libc6-dev-i386 lib32ncurses5-dev x11proto-core-dev libx11-dev lib32z-dev libgl1-mesa-dev libxml2-utils xsltproc unzip

Step 4: Configure your smart phone access

I next installed the tools required to access the phone. This access would be required to later flash the phone or access its internals with ADB.

sudo apt-get install android-tools-adb
sudo apt-get install fastboot

Step 5: To creating the work directories i typed the following commands. I was following the instructions from the above two articles alternately.

mkdir -p ~/bin
mkdir -p ~//lineage

Step 6: Installing repo

I was informed that the Android source tree is located in a Git repository which is hosted by Google. The Git repository includes metadata for the Android source. Repo is a tool that makes it easier to work with Git .

curl [url]https://storage.googleapis.com/git-repo-downloads/repo[/url] > ~/bin/repo

Once the repo was downloaded I had to make it executable

chmod a+x ~/bin/repo

Step 7: The next step was to initialize the lineage source

This required to change to the directory created in step number 5 above. As someone coming from the world of windows I preferred to use the GUI and open the lineage folder created by using the mouse click. There right click brings up the option of ' Open in Terminal' . Those who prefer to type commands can use the below command

cd ~//lineage

Once I had made sure that I was in the newly created lineage folder I moved ahead.

Step 8: Now i was required to configure my Git user

git config --global user.name "Your Name"
git config --global user.email "you@example.com"

I replaced the text within the " " with my creadentials, which I had created on https://github.com/

Step 9: Now we moved on to initializing the repo

repo init -u [url]https://github.com/LineageOS/android.git[/url] -b lineage-15.1

A successful initialization showed a message stating that Repo is initialized in your working directory. The lineage directory now contain a .repo folder. To check hidden folder I used control + H key.

Step 8: Download the source code

This is the step where you will realize the importance of having a fast internet connection. The source code size is about 30 – 35 GB. I have a 10 mbps line and at times the download speed shoots up to 20- 25 mbps!!!* Yet it takes me anything from 4 – 10 hours to download the entire code!

My suggestion is check the time when your local ISP download speeds are at its best. For me it is during the night. I set the download up at night and go to sleep!

The command to get the source code is :

repo sync -c -f --force-sync --no-clone-bundle --no-tags --optimized-fetch –prune

Optional Step 8 a: Making a backup of your source code

I copied the entire folder and kept a copy on an external device. This is just in case there is any need for me to format my hard disk. While copying I do not copy the .Repo and .Cache folders on to my backup. To check hidden folders press control + H keys.

Step 9: Get the source code for your specific device.

This is where I was stuck numerous times. As I understood the code which was downloaded is generic in nature. For your particular device you would need to get files which are specific to your device.

The source for all these files is github. You are targeting three sets of folders – Device, Kernel and vendor.

The git clone commands given below are for the tissot or Xiaomi MiA1 phone. Similarly other phones have their locations on GitHub from where you can get files specific to them.

git clone [url]https://github.com/TheScarastic/andr...msm8953-common[/url] -b lineage-15.1 device/xiaomi/msm8953
git clone [url]https://github.com/TheScarastic/andr..._xiaomi_tissot[/url] -b lineage-15.1 device/xiaomi/tissot
git clone [url]https://github.com/TheScarastic/prop..._vendor_xiaomi[/url] -b lineage-15.1 vendor/xiaomi
git clone [url]https://github.com/Tissot-Developmen..._xiaomi_tissot[/url] -b 8.1 kernel/xiaomi/msm8953

Step 10: Modify Caching to speed up the build process.

export CCACHE_DIR=./.ccache
ccache -C
export USE_CCACHE=1
export CCACHE_COMPRESS=1
prebuilts/misc/linux-x86/ccache/ccache -M 50G

Step 11: Configure JACK

JACK is the java compiler and can cause crashes – believe me! A simple fix is this command which you type next

export _JACK_VM_ARGS="-Dfile.encoding=UTF-8 -XX:+TieredCompilation -Xmx4G"

Step 12: Cleaning up the build folder

make clean

Step 13: Initializing the build

source build/envsetup.sh

Step 14: Starting the build

croot
brunch tissot

Watching the build on the screen is an interesting phase. It can get a bit tedious. In my case it took about 3 hours to complete the build. There were numerous errors that were thrown up. Files were declared as missing. After a couple of failures I realized I could search for them and then paste the file in the appropriate folders.

The one good thing about the build errors is googling for them usually gets you the right help. There would definitely be someone in some part of the world who would have run into a similar issue.

Finally after a 3 hour wait I got my zip file which when i flashed through TWRP on my MiA1. The sheer joy of having a ROM you created on your phone is indeed beyond words. It took me about a week of sitting for about ten to fifteen hours to get the various combination right, but believe me when I tell you the results are worth it.

My thanks to arunassain https://xdaforums.com/member.php?u=6768248 from whose article I was able to understand the basics. He helped me with responses to my queries when I was stuck.

I further picked up from the excellent articles under the title Establishing a build Environment at https://source.android.com/setup/build/initializing

A great video that helped me was available on the topic How to build your own custom Android ROM at https://www.androidauthority.com/build-custom-android-rom-720453/

To check out the ROM's built for the MiA1 please click here

Now coming to the question if I have understood everything that is to learn about ROM development, well the answer is no. This was just the first build by a noob of a ROM which somehow worked. I have been using the ROM on my daily driver for the past one day and it is working perfectly. Having said that I still need to understand more of what happens behind the scenes in this wonder world of Custom ROM development.