diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
index bca61608ff..2bf22a1d0b 100644
--- a/docs/system/arm/sbsa.rst
+++ b/docs/system/arm/sbsa.rst
@@ -1,12 +1,16 @@
 Arm Server Base System Architecture Reference board (``sbsa-ref``)
 ==================================================================
 
-While the ``virt`` board is a generic board platform that doesn't match
-any real hardware the ``sbsa-ref`` board intends to look like real
-hardware. The `Server Base System Architecture
-<https://developer.arm.com/documentation/den0029/latest>`_ defines a
-minimum base line of hardware support and importantly how the firmware
-reports that to any operating system.
+The ``sbsa-ref`` board intends to look like real hardware (while the ``virt``
+board is a generic board platform that doesn't match any real hardware).
+
+The hardware part is defined by two specifications:
+
+  - `Base System Architecture <https://developer.arm.com/documentation/den0094/>`__ (BSA)
+  - `Server Base System Architecture <https://developer.arm.com/documentation/den0029/>`__ (SBSA)
+
+The `Arm Base Boot Requirements <https://developer.arm.com/documentation/den0044/>`__ (BBR)
+specification defines how the firmware reports that to any operating system.
 
 It is intended to be a machine for developing firmware and testing
 standards compliance with operating systems.
@@ -35,16 +39,29 @@ includes both internal hardware and parts affected by the qemu command line
 (i.e. CPUs and memory). As a result it must have a firmware specifically built
 to expect a certain hardware layout (as you would in a real machine).
 
+Note
+''''
+
+QEMU provides the guest EL3 firmware with minimal information about hardware
+platform using minimalistic devicetree. This is not a Linux devicetree. It is
+not even a firmware devicetree.
+
+It is information passed from QEMU to describe the information a hardware
+platform would have other mechanisms to discover at runtime, that are affected
+by the QEMU command line.
+
+Ultimately this devicetree may be replaced by IPC calls to an emulated SCP.
+
 DeviceTree information
 ''''''''''''''''''''''
 
-The devicetree provided by the board model to the firmware is not intended
-to be a complete compliant DT. It currently reports:
+The devicetree reports:
 
    - CPUs
    - memory
    - platform version
    - GIC addresses
+   - NUMA node id for CPUs and memory
 
 Platform version
 ''''''''''''''''
@@ -70,4 +87,4 @@ Platform version changes:
   GIC ITS information is present in devicetree.
 
 0.3
-  The USB controller is an XHCI device, not EHCI
+  The USB controller is an XHCI device, not EHCI.