diff --git a/docs/arm64.md b/docs/arm64.md
index 7e451a8cc..44b059d9a 100644
--- a/docs/arm64.md
+++ b/docs/arm64.md
@@ -7,39 +7,6 @@ booting and direct-kernel booting. The document covers both methods.
 All the steps are based on Ubuntu. We use the Ubuntu cloud image for guest VM
 disk.
 
-## Getting started
-
-We create a folder to build and run Cloud Hypervisor at `$HOME/cloud-hypervisor`
-
-```shell
-$ export CLOUDH=$HOME/cloud-hypervisor
-$ mkdir $CLOUDH
-```
-
-## Prerequisites
-
-You need to install some prerequisite packages to build and test Cloud Hypervisor.
-
-### Tools
-
-```bash
-# Install rust tool chain
-$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
-# Install the tools used for building guest kernel, EDK2 and converting guest disk
-$ sudo apt-get update
-$ sudo apt-get install git build-essential m4 bison flex uuid-dev qemu-utils
-```
-
-### Building Cloud Hypervisor
-
-```bash
-$ pushd $CLOUDH
-$ git clone https://github.com/cloud-hypervisor/cloud-hypervisor.git
-$ cd cloud-hypervisor
-$ cargo build
-$ popd
-```
-
 ### Disk image
 
 Download the Ubuntu cloud image and convert the image type.
diff --git a/docs/building.md b/docs/building.md
index 419b0f75f..847ac6c9b 100644
--- a/docs/building.md
+++ b/docs/building.md
@@ -24,12 +24,15 @@ Hypervisor. Here, all the steps are based on Ubuntu, for other Linux
 distributions please replace the package manager and package name.
 
 ```shell
-# Install build-essential, git, and qemu-utils
-$ sudo apt install git build-essential qemu-utils
+# Install basic packages needed. For a package list targeting for more
+# functionalities for example the test, please see resources/Dockerfile.
+$ sudo apt-get update
+$ sudo apt install git build-essential m4 bison flex uuid-dev qemu-utils
 # Install rust tool chain
 $ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
 # If you want to build statically linked binary please add musl target
-$ rustup target add x86_64-unknown-linux-musl
+$ rustup target add x86_64-unknown-linux-musl  # x86-64
+$ rustup target add aarch64-unknown-linux-musl # AArch64
 ```
 
 ## Clone and build
@@ -46,7 +49,8 @@ $ cargo build --release
 $ sudo setcap cap_net_admin+ep ./target/release/cloud-hypervisor
 
 # If you want to build statically linked binary
-$ cargo build --release --target=x86_64-unknown-linux-musl --all
+$ cargo build --release --target=x86_64-unknown-linux-musl --all  # x86-64
+$ cargo build --release --target=aarch64-unknown-linux-musl --all # AArch64
 $ popd
 ```