diff --git a/Makefile.base b/Makefile.base
index 0c5da103d1..ef5d77effe 100644
--- a/Makefile.base
+++ b/Makefile.base
@@ -68,7 +68,9 @@ $(BINDIR)/$(MODULE)/:
 $(BINDIR)/$(MODULE).a $(OBJ): | $(BINDIR)/$(MODULE)/
 
 $(BINDIR)/$(MODULE).a: $(OBJ) | ${DIRS:%=ALL--%}
-	$(Q)$(AR) $(ARFLAGS) $@ $?
+	@# Recreate archive to cleanup deleted/non selected source files objects
+	$(Q)$(RM) $@
+	$(Q)$(AR) $(ARFLAGS) $@ $^
 
 CXXFLAGS = $(filter-out $(CXXUWFLAGS), $(CFLAGS)) $(CXXEXFLAGS)
 CCASFLAGS = $(filter-out $(CCASUWFLAGS), $(CFLAGS)) $(CCASEXFLAGS)
diff --git a/doc/doxygen/src/creating-modules.md b/doc/doxygen/src/creating-modules.md
index 63d2c840d6..82d54be000 100644
--- a/doc/doxygen/src/creating-modules.md
+++ b/doc/doxygen/src/creating-modules.md
@@ -34,6 +34,20 @@ current configuration or not.
 Modules can be used by adding their name to the `USEMODULE` macro of your
 application's Makefile.
 
+### Pitfalls ###
+
+The `MODULE` name should be unique or build breaks as modules overwrite the
+same output file.
+
+This problem happened in the past for:
+
+ * Packages root directory (libfixmath/u8g2)
+ * boards/cpu/periph and their common boards/cpu/periph
+
+Note: even if all boards and cpus implement the `board` and `cpu` modules, only
+      one is used in an application so there is no conflict.
+
+
 Module dependencies
 ===================
 Your module may depend on other modules to minimize code duplication. These