diff --git a/Readme.md b/Readme.md
index 6acf0a7..06ed17d 100644
--- a/Readme.md
+++ b/Readme.md
@@ -8,6 +8,8 @@ and [draft-ietf-doh-dns-over-https](https://github.com/dohwg/draft-ietf-doh-dns-
 
 Install [Go](https://golang.org), at least version 1.9.
 
+(Note for Debian/Ubuntu users: You need to set `$GOROOT` if you could not get your new version of Go selected by the Makefile.)
+
 First create an empty directory, used for `$GOPATH`:
 
     mkdir ~/gopath