diff --git a/share/man/man7/build.7 b/share/man/man7/build.7
--- a/share/man/man7/build.7
+++ b/share/man/man7/build.7
@@ -683,6 +683,10 @@
 and
 .Cm installkernel
 process.
+This is currently incompatible with building
+.Pa src
+into
+.Cm packages .
 .Bd -literal
 make PORTS_MODULES=emulators/virtualbox-ose-kmod kernel
 .Ed