diff --git a/README.md b/README.md
index 210f70e..2fb20bf 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@
 
 AVF components:
 * [pVM firmware](pvmfw/README.md)
+* [Android Boot Loader (ABL)](docs/abl.md)
 * [Microdroid](microdroid/README.md)
 * [Microdroid kernel](microdroid/kernel/README.md)
 * [Microdroid payload](microdroid/payload/README.md)
@@ -29,4 +30,4 @@
 * [Building and running a demo app in C++](demo_native/README.md)
 * [Debugging](docs/debug)
 * [Using custom VM](docs/custom_vm.md)
-* [Device assignment](docs/device_assignment.md)
\ No newline at end of file
+* [Device assignment](docs/device_assignment.md)
diff --git a/docs/abl.md b/docs/abl.md
new file mode 100644
index 0000000..b08464e
--- /dev/null
+++ b/docs/abl.md
@@ -0,0 +1,53 @@
+# Android Bootloader (ABL)
+
+[ABL](https://source.android.com/docs/core/architecture/bootloader) is not a component of AVF, but
+it plays a crucial role in loading the necessary AVF components and initializing them in a correct
+way. This doc explains the responsibilities of ABL from the perspective of AVF.
+
+## pVM firmware (pvmfw)
+
+ABL is responsible for the followings:
+
+* locating pvmfw binary from the pvmfw partition,
+* verifying it as part of the [verified
+  boot](https://source.android.com/docs/security/features/verifiedboot) process,
+* loading it into memory, and
+* describing the region where pvmfw is loaded using DT and passing it to hypervisor.
+
+See [ABL Support](../pvmfw/README.md#android-bootloader-abl_support) for more detail.
+
+ABL is also responsible for constructing the pvmfw configuration data. The data consists of the
+following info:
+
+* DICE chain (also known as BCC Handover)
+* DTBO describing [debug policy](debug/README.md#debug-policy) (if available)
+* DTBO describing [assignable devices](device_assignment.md) (if available)
+* Reference DT carrying extra information that needs to be passed to the guest VM
+
+See [Configuration Data](../pvmfw/README.md#configuration-data) for more detail.
+
+## Android
+
+ABL is responsible for setting the following bootconfigs describing the status and capabilities of
+the hypervisor.
+
+* `androidboot.hypervisor.version`: free-form description of the hypervisor
+* `androidboot.hypervisor.vm.supported`: whether traditional VMs (i.e.  non-protected VMS) are
+  supported or not
+* `androidboot.hypervisor.protected_vm.supported`: whether protected VMs are supported or not
+
+Thee bootconfigs are converted into system properties by the init process.
+
+See
+[HypervisorProperties.prop](https://android.googlesource.com/platform/system/libsysprop/+/refs/heads/main/srcs/android/sysprop/HypervisorProperties.sysprop)
+for more detail.
+
+
+
+
+
+
+
+
+
+