diff --git a/Arduino.mk b/Arduino.mk
index c1981d0..8740b77 100644
--- a/Arduino.mk
+++ b/Arduino.mk
@@ -712,12 +712,15 @@ LOCAL_CC_SRCS   ?= $(wildcard *.cc)
 LOCAL_PDE_SRCS  ?= $(wildcard *.pde)
 LOCAL_INO_SRCS  ?= $(wildcard *.ino)
 LOCAL_AS_SRCS   ?= $(wildcard *.S)
+LOCAL_SUBF_SRCS ?= $(foreach dir,$(SOURCE_FOLDERS),$(wildcard $(dir)/*.cpp))
 LOCAL_SRCS      = $(LOCAL_C_SRCS)   $(LOCAL_CPP_SRCS) \
 		$(LOCAL_CC_SRCS)   $(LOCAL_PDE_SRCS) \
-		$(LOCAL_INO_SRCS) $(LOCAL_AS_SRCS)
+		$(LOCAL_INO_SRCS) $(LOCAL_AS_SRCS) \
+        $(LOCAL_SUBF_SRCS)
 LOCAL_OBJ_FILES = $(LOCAL_C_SRCS:.c=.o)   $(LOCAL_CPP_SRCS:.cpp=.o) \
 		$(LOCAL_CC_SRCS:.cc=.o)   $(LOCAL_PDE_SRCS:.pde=.o) \
-		$(LOCAL_INO_SRCS:.ino=.o) $(LOCAL_AS_SRCS:.S=.o)
+		$(LOCAL_INO_SRCS:.ino=.o) $(LOCAL_AS_SRCS:.S=.o) \
+        $(LOCAL_SUBF_SRCS:.cpp=.o)
 LOCAL_OBJS      = $(patsubst %,$(OBJDIR)/%,$(LOCAL_OBJ_FILES))
 
 ifeq ($(words $(LOCAL_SRCS)), 0)