diff --git a/README b/README
new file mode 100644
index 0000000..46dd1b9
--- /dev/null
+++ b/README
@@ -0,0 +1,19 @@
+# Download Kernel source
+ Refer to https://source.android.com/setup/build/building-kernels
+
+ Make separate kernel directory apart from Android source.
+
+  $ cd <kernel directory>
+  $ repo init -u https://github.com/android-rpi/kernel_manifest -b arpi-5.10
+  $ repo sync
+ 
+# Build Kernel
+  $ build/build.sh
+
+  Output files are under out/arpi-5.10/dist/
+    Image.gz
+    bcm2711-rpi-*.dtb
+    vc4-kms-v3d-pi4.dtbo
+
+# Build Android for Raspberry Pi 4
+ https://github.com/android-rpi/device_arpi_rpi4
diff --git a/default.xml b/default.xml
index 97e90fe..138c64b 100644
--- a/default.xml
+++ b/default.xml
@@ -1,22 +1,29 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <manifest>
-  <remote  name="aosp" fetch=".." review="https://android-review.googlesource.com/" />
-  <default revision="master" remote="aosp" sync-j="4" />
+  <remote  name="aosp" fetch="https://android.googlesource.com" review="https://android-review.googlesource.com/" />
+  <default revision="master-kernel-build-2021" remote="aosp" sync-j="4" />
+
+  <superproject name="kernel/superproject" remote="aosp"/>
 
   <project path="build" name="kernel/build" />
   <project path="hikey-modules" name="kernel/hikey-modules" revision="android12-5.10" />
   <project path="common" name="kernel/common" revision="android12-5.10" />
-  <project path="kernel/common-patches" name="kernel/common-patches" >
+  <project path="kernel/common-patches" name="kernel/common-patches" revision="master">
       <linkfile src="android-mainline" dest="common/patches" />
   </project>
   <project path="kernel/tests" name="kernel/tests" />
   <project path="kernel/configs" name="kernel/configs" revision="master" />
   <project path="common-modules/virtual-device" name="kernel/common-modules/virtual-device" revision="android12-5.10" />
-  <project path="prebuilts/gas/linux-x86" name="platform/prebuilts/gas/linux-x86" clone-depth="1" />
   <project path="prebuilts-master/clang/host/linux-x86" name="platform/prebuilts/clang/host/linux-x86" clone-depth="1" />
   <project path="prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.17-4.8" name="platform/prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.17-4.8" clone-depth="1" />
   <project path="prebuilts/boot-artifacts" name="platform/prebuilts/boot-artifacts" />
   <project path="prebuilts/build-tools" name="platform/prebuilts/build-tools" clone-depth="1" />
   <project path="prebuilts/kernel-build-tools" name="kernel/prebuilts/build-tools" clone-depth="1" />
-  <project path="tools/mkbootimg" name="platform/system/tools/mkbootimg" />
+  <project path="tools/mkbootimg" name="platform/system/tools/mkbootimg" revision="master" />
+
+  <remote  name="arpi" fetch="."/>
+  <remove-project name="kernel/common"/>
+  <project path="common" name="kernel_arpi" revision="arpi-5.10" remote="arpi">
+      <linkfile src="build.config.arpi" dest="build.config"/>
+  </project>
 </manifest>