diff --git a/docs/Building.md b/docs/Building.md
index 2e6c66e6..b009b371 100644
--- a/docs/Building.md
+++ b/docs/Building.md
@@ -79,6 +79,19 @@ PIC is enabled by default and can be disabled with
 2. Install doxygen and ccache through brew: `brew install doxygen ccache`
 3. Install the GStreamer runtime and developement packages according to [these instructions](https://gstreamer.freedesktop.org/documentation/installing/on-mac-osx.html?gi-language=c#download-and-install-the-sdk)
 
+
+## ARM notes
+
+The MXL project is configured to require the `armv8.5-a` architecture on ARM CPUs.  Most modern ARM CPUs meet this requirement.  Notable exceptions are the Raspberry Pis.  For example, the Pi 5 CPU has an architecture level `armv8.2-a` whereas the Pi 4 Model B is at level `armv8.0-a`.  To properly target these CPUs, pass the architecture type as an additional argument to cmake : `-DMXL_TARGET_ARCH=<archname>`.
+
+For example, for the Raspberry Pi 5:
+```
+mkdir build
+cd build
+cmake .. --preset Linux-GCC-Debug -DMXL_TARGET_ARCH=armv8.2a
+cmake --build build/Linux-GCC-Debug --target all
+```
+
 # Using with CMake
 
 The MXL provides a CMake package configuration file that allows for easy integration into your project. If it is installed in a non-default location, you may need to specify its root path using `CMAKE_PREFIX_PATH`: