diff --git a/README.md b/README.md
index ff0b56b..4a9be6e 100644
--- a/README.md
+++ b/README.md
@@ -108,10 +108,10 @@ go build ./cmd/uncanny
 
 Note that CGO is required because the source code makes use of the global
 `messages.h` C header file. If you need to cross-compile, use the following
-command:
+command (-a cleans the cache, may be necessary when messages.h changes):
 
 ```shell
-GOARCH=arm GOOS=linux CGO_ENABLED=1 CC=arm-linux-gnueabi-gcc go build -o uncanny-linux-arm ./cmd/uncanny
+GOARCH=arm GOOS=linux CGO_ENABLED=1 CC=arm-linux-gnueabi-gcc go build -a -o uncanny-linux-arm ./cmd/uncanny
 ```
 
 The resulting `uncanny` executable should be running on the controlling