diff --git a/docs/fdroid.texi b/docs/fdroid.texi
index fc8c6c83..ab304563 100644
--- a/docs/fdroid.texi
+++ b/docs/fdroid.texi
@@ -911,6 +911,10 @@ As for 'prebuild', but runs during the actual build phase (but before the
 main ant/maven build). Use this only for actions that do actual building.
 Any prepartion of the source code should be done using 'init' or 'prebuild'.
 
+Any building that takes place before build= will be ignored, as either ant,
+mvn or gradle will be executed to clean the build environment right before
+build= (or the final build) is run.
+
 You can use $$SDK$$, $$NDK$$ and $$MVN3$$ to substitute the paths to the
 android SDK and NDK directories, and maven 3 executable respectively.