diff --git a/doc/board/apple/m1.rst b/doc/board/apple/m1.rst
index 9fa2176..083bfb0 100644
--- a/doc/board/apple/m1.rst
+++ b/doc/board/apple/m1.rst
@@ -7,18 +7,21 @@
 developed by the Asahi Linux project.  At this point the machines with
 the following SoCs work:
 
- - Apple M1 SoC
+ - Apple M1 SoC (t8103)
+ - Apple M1 Pro SoC (t6000)
+ - Apple M1 Max SoC (t6001)
 
 On these SoCs the following hardware is supported:
 
  - S5L serial port
+ - SPI keyboard (on laptops)
  - Framebuffer
+ - NVMe storage
  - USB 3.1 Type-C ports
 
-Device trees are currently provided for the M1 Mac mini (2020, J274)
-and M1 MacBook Pro 13" (2020, J293).  The M1 MacBook Air (2020) is
-expected to work with the J293 device tree.  The M1 iMac (2021) may
-work with the J274 device tree.
+Device trees are currently provided for the M1 Mac mini (2020, J274),
+M1 MacBook Pro 13" (2020, J293), M1 MacBook Air (2020, J313) and M1
+iMac (2021, J456/J457).
 
 Building U-Boot
 ---------------
@@ -57,3 +60,23 @@
     https://github.com/AsahiLinux/docs/wiki/Developer-Quickstart
 
 Just replace ``m1n1.macho`` with ``u-boot.macho`` in the instructions.
+
+Debug UART
+----------
+
+Since the base address of the UART is SoC-dependent, the debug UART is
+not enabled by default.  To enable the debug UART the base address
+needs to be adjusted and the CONFIG_DEBUG_UART option needs to be
+enabled.  The table below gives the correct base address for the
+supported SoCs.
+
+.. list-table::
+   :widths: 32 16
+   :header-rows: 1
+
+   * - SoC
+     - Base Address
+   * - M1 (t8103)
+     - 0x235200000
+   * - M1 Pro/Max (t6000/t6001)
+     - 0x39b200000