diff --git a/README.md b/README.md
index 25c0a02d..6abf52c0 100644
--- a/README.md
+++ b/README.md
@@ -170,9 +170,9 @@ example of compilation console output
 RTLPlayground/installer$ make
 mkdir -p output
 gcc updatebuilder.c -o output/updatebuilder
-sdas8051 -plosgff -o output/crtstart.rel crtstart.asm
-sdcc -mmcs51 --code-loc 0x1000 -o output/installer.rel -c installer.c
-sdcc -mmcs51 -Wl-bHOME=0x1100 -Wl-r -o output/rtlinstaller.ihx output/crtstart.rel output/installer.rel
+../toolchain/sdcc-3390765201/bin/sdas8051 -plosgff -o output/crtstart.rel crtstart.asm
+../toolchain/sdcc-3390765201/bin/sdcc -mmcs51 --code-loc 0x1000 -o output/installer.rel -c installer.c
+../toolchain/sdcc-3390765201/bin/sdcc -mmcs51 -Wl-bHOME=0x1100 -Wl-r -o output/rtlinstaller.ihx output/crtstart.rel output/installer.rel
 ./output/updatebuilder -i output/rtlinstaller.ihx -o output/rtlplayground_oem_upgrade.bin ../output/rtlplayground.bin
 Input file size: 524288
 Bytes read: 524288
diff --git a/installer/Makefile b/installer/Makefile
index c451f499..1aeef985 100644
--- a/installer/Makefile
+++ b/installer/Makefile
@@ -1,9 +1,14 @@
 CODE_LOCATION=0x1000
 INSTALLER_ADDRESS=0x1100
 
-CC = sdcc
+SDCC_PREFIX = ../toolchain/sdcc-$(shell cat ../sdcc/* | cksum | cut -d' ' -f1)
+ifeq ($(origin CC),default)
+SDCC = $(SDCC_PREFIX)/bin/sdcc
+CC = $(SDCC)
+ASM = $(SDCC_PREFIX)/bin/sdas8051
+endif
 CC_FLAGS = -mmcs51
-ASM = sdas8051
+ASM ?= sdas8051
 AFLAGS= -plosgff
 
 BUILDDIR = output
@@ -13,9 +18,14 @@ OBJS = ${SRCS:%.c=$(BUILDDIR)/%.rel}
 
 all: create_build_dir $(BUILDDIR)/updatebuilder $(BUILDDIR)/rtlplayground_oem_upgrade.bin
 
-create_build_dir:
+create_build_dir: $(SDCC)
 	mkdir -p $(BUILDDIR)
 
+ifneq ($(SDCC),)
+$(SDCC):
+	sh ../sdcc/build.sh $(abspath $(SDCC_PREFIX))
+endif
+
 $(BUILDDIR)/updatebuilder: updatebuilder.c
 	gcc $^ -o $@