diff --git a/doc/test-runner.txt b/doc/test-runner.txt
index 3660381a..ccc17f7b 100644
--- a/doc/test-runner.txt
+++ b/doc/test-runner.txt
@@ -69,6 +69,16 @@ After that a default kernel with the required options can be built:
 
 	$ make -j$(nproc)
 
+Note: If your host distribution does not contain a regulatory.db you may get an
+error similar to this when building the kernel:
+
+No rule to make target '/lib/firmware/regulatory.db'...
+
+To fix this you must download the regulatory.db manually and place it in
+/lib/firmware. This can be found here:
+
+https://git.kernel.org/pub/scm/linux/kernel/git/sforshee/wireless-regdb.git
+
 Note: To catch locking related issues the following set of kernel config
 options may be useful: