diff --git a/docs/lesson00/rpi-os.md b/docs/lesson00/rpi-os.md
index d0a5729f..e0db9435 100644
--- a/docs/lesson00/rpi-os.md
+++ b/docs/lesson00/rpi-os.md
@@ -176,6 +176,17 @@ raspi2               Raspberry Pi 2
 raspi3               Raspberry Pi 3
 ```
 
+Confirm you have the GNU C compiler for the arm64 architecture
+
+```
+which aarch64-linux-gnu-gcc
+```
+
+If the arm64 compiler isn't found (no response from terminal), install the compiler
+```
+sudo apt-get install gcc-aarch64-linux-gnu
+```
+
 Test QEMU with Rpi3 baremetal code
 
 ```