diff --git a/Makefile b/Makefile
index b5271d4..0e43d55 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,7 @@
 # Set the TARGETS and PROGRAM values as required.
 # See makefiles/build.mk for details on directory structure for src files and how to add custom extensions to the build.
 
-TARGETS = atari c64 apple2 apple2enh
-#TARGETS = atari
+TARGETS = atari c64 apple2 apple2enh coco
 PROGRAM := fujinet.lib
 
 SUB_TASKS := clean disk test release
diff --git a/Makefile.coco b/Makefile.coco
deleted file mode 100644
index 8e9b575..0000000
--- a/Makefile.coco
+++ /dev/null
@@ -1,214 +0,0 @@
-##
-## Temporary Makefile for CoCo
-## intended to be used as reference as its functions are refactored
-## into the main Makefile
-##
-## Author: Thom Cherryhomes <thom.cherryhomes@gmail.com>
-##
-
-# Adapted from the generic cc65 makefile.
-# Notible exceptions:
-# - recursive dirs for src
-# - final files go into build/ directory instead of root folder (e.g. lbl, com file etc)
-
-TARGETS := coco
-PROGRAM := fujinet.lib
-LIBS    :=
-CONFIG  :=
-CFLAGS  =
-ASFLAGS =
-LDFLAGS =
-SRCDIR := src
-OBJDIR := obj
-EMUCMD :=
-BUILD_DIR = build
-CC	:= cmoc
-AS	:= lwasm
-AR	:= lwar
-
-# The subfolder src directory to use to build the particular target
-# cl65 will get the "TARGET" name, but the src folder will be the "PLATFORM"
-PLATFORM_coco          := coco
-
-TARGETOBJDIR := $(OBJDIR)/$(TARGETS)
-
-ifeq ($(shell echo),)
-  MKDIR = mkdir -p $1
-  RMDIR = rmdir $1
-  RMFILES = $(RM) $1
-else
-  MKDIR = mkdir $(subst /,\,$1)
-  RMDIR = rmdir $(subst /,\,$1)
-  RMFILES = $(if $1,del /f $(subst /,\,$1))
-endif
-COMMA := ,
-SPACE := $(N/A) $(N/A)
-define NEWLINE
-
-
-endef
-# Note: Do not remove any of the two empty lines above !
-
-rwildcard=$(wildcard $(1)$(2))$(foreach d,$(wildcard $1*), $(call rwildcard,$d/,$2))
-
-TARGETLIST := $(subst $(COMMA),$(SPACE),$(TARGETS))
-
-ifeq ($(words $(TARGETLIST)),1)
-
-PLATFORM_SRC_DIR := $(PLATFORM_$(TARGETLIST))/$(SRCDIR)
-
-# Set PROGRAM to something like 'myprog.c64'.
-override PROGRAM := $(PROGRAM).$(TARGETLIST)
-
-# Recursive files
-SOURCES += $(call rwildcard,$(PLATFORM_SRC_DIR)/,*.s)
-SOURCES += $(call rwildcard,$(PLATFORM_SRC_DIR)/,*.c)
-SOURCES += $(call rwildcard,common/$(SRCDIR)/,*.s)
-SOURCES += $(call rwildcard,common/$(SRCDIR)/,*.c)
-
-# remove trailing and leading spaces.
-SOURCES := $(strip $(SOURCES))
-
-# convert from src/your/long/path/foo.[c|s] to obj/your/long/path/foo.o
-OBJ1 := $(SOURCES:.c=.o)
-OBJECTS := $(OBJ1:.s=.o)
-# change from atari/src/ -> obj/atari/
-OBJECTS := $(OBJECTS:$(PLATFORM_SRC_DIR)/%=$(OBJDIR)/$(TARGETLIST)/%)
-OBJECTS := $(OBJECTS:common/$(SRCDIR)/%=$(OBJDIR)/common/%)
-
-DEPENDS := $(OBJECTS:.o=.d)
-
-LIBS += $(wildcard $(PLATFORM_SRC_DIR)/*.lib)
-
-ASFLAGS += \
-	--asm-include-dir common/inc \
-	--asm-include-dir $(PLATFORM_SRC_DIR)/include \
-	--asm-include-dir .
-
-CFLAGS += \
-    -O2 \
-	-I common/inc \
-	-I $(PLATFORM_SRC_DIR)/include \
-	-I .
-
-CHANGELOG = Changelog.md
-
-# single line with version number in semantic form (e.g. 2.1.3)
-VERSION_FILE = version.txt
-VERSION_STRING := $(file < $(VERSION_FILE))
-
-# include files that are included in the ZIP dist/release target
-FN_NW_HEADER = fujinet-network.h
-FN_NW_INC = fujinet-network.inc
-FN_FUJI_HEADER = fujinet-fuji.h
-FN_FUJI_INC = fujinet-fuji.inc
-
-define _listing_
-  CFLAGS += --listing $$(@:.o=.lst)
-  ASFLAGS += --listing $$(@:.o=.lst)
-endef
-
-define _mapfile_
-  LDFLAGS += --mapfile $$@.map
-endef
-
-define _labelfile_
-  LDFLAGS += -Ln $$@.lbl
-endef
-
-.SUFFIXES:
-.PHONY: all clean dist fujinet.lib.$(TARGETLIST)
-
-all: fujinet.lib.$(TARGETLIST)
-
-STATEFILE := Makefile.options
--include $(DEPENDS)
--include $(STATEFILE)
-
-ifeq ($(origin _OPTIONS_),file)
-OPTIONS = $(_OPTIONS_)
-$(eval $(OBJECTS): $(STATEFILE))
-endif
-
-# Transform the abstract OPTIONS to the actual cc65 options.
-$(foreach o,$(subst $(COMMA),$(SPACE),$(OPTIONS)),$(eval $(_$o_)))
-
-$(OBJDIR):
-	$(call MKDIR,$@)
-
-$(TARGETOBJDIR):
-	$(call MKDIR,$@)
-
-$(BUILD_DIR):
-	$(call MKDIR,$@)
-
-SRC_INC_DIRS := \
-	$(sort $(dir $(wildcard $(PLATFORM_SRC_DIR)/*))) \
-	$(sort $(dir $(wildcard common/$(SRCDIR)/*)))
-
-# $(info $$SOURCES = ${SOURCES})
-# $(info $$OBJECTS = ${OBJECTS})
-# $(info $$SRC_INC_DIRS = ${SRC_INC_DIRS})
-# $(info $$ASFLAGS = ${ASFLAGS})
-# $(info $$TARGETOBJDIR = ${TARGETOBJDIR})
-# $(info $$TARGETLIST = ${TARGETLIST})
-
-vpath %.c $(SRC_INC_DIRS)
-
-obj/common/%.o: %.c | $(TARGETOBJDIR)
-	@$(call MKDIR,$(dir $@))
-	$(CC) -c --deps $(CFLAGS) -o $@ $<
-
-$(TARGETOBJDIR)/%.o: %.c | $(TARGETOBJDIR)
-	@$(call MKDIR,$(dir $@))
-	$(CC) -c --deps $(CFLAGS) -o $@ $<
-
-# vpath %.s $(SRC_INC_DIRS)
-
-# obj/common/%.o: %.s | $(TARGETOBJDIR)
-# 	@$(call MKDIR,$(dir $@))
-# 	$(AS) -c --deps $(ASFLAGS) -o $@ $<
-
-$(TARGETOBJDIR)/%.o: %.s | $(TARGETOBJDIR)
-	@$(call MKDIR,$(dir $@))
-	$(CC) -c --deps $(@:.o=.d) $(ASFLAGS) -o $@ $<
-
-$(BUILD_DIR)/$(PROGRAM): $(OBJECTS) | $(BUILD_DIR)
-	$(AR) $@ -a $(OBJECTS)
-
-$(PROGRAM): $(BUILD_DIR)/$(PROGRAM) | $(BUILD_DIR)
-
-clean:
-	$(call RMFILES,$(OBJECTS))
-	$(call RMFILES,$(DEPENDS))
-	$(call RMFILES,$(REMOVES))
-	$(call RMFILES,$(BUILD_DIR)/$(PROGRAM))
-
-dist: $(PROGRAM)
-	$(call MKDIR,dist/)
-	$(call RMFILES,dist/fujinet-$(TARGETLIST)-*.lib)
-	cp build/$(PROGRAM) dist/fujinet-$(TARGETLIST)-$(VERSION_STRING).lib
-	cp $(FN_NW_HEADER) dist/
-	cp $(FN_NW_INC) dist/
-	cp $(FN_FUJI_HEADER) dist/
-	cp $(FN_FUJI_INC) dist/
-	cp $(CHANGELOG) dist/
-	cd dist && zip fujinet-lib-$(TARGETLIST)-$(VERSION_STRING).zip $(CHANGELOG) fujinet-$(TARGETLIST)-$(VERSION_STRING).lib *.h *.inc
-	$(call RMFILES,dist/fujinet-$(TARGETLIST)-*.lib)
-	$(call RMFILES,dist/$(CHANGELOG))
-	$(call RMFILES,dist/*.h)
-	$(call RMFILES,dist/*.inc)
-
-else # $(words $(TARGETLIST)),1
-
-all:
-	$(foreach t,$(TARGETLIST),$(MAKE) TARGETS=$t clean all dist$(NEWLINE))
-
-endif # $(words $(TARGETLIST)),1
-
-
-###################################################################
-###  Place your additional targets in the additional Makefiles  ###
-### in the same directory - their names have to end with ".mk"! ###
-###################################################################
--include *.mk
diff --git a/atari/src/fn_fuji/fuji_appkey_open_read.c b/atari/src/fn_fuji/fuji_appkey_open_read.c
index 13656d6..3d73a00 100644
--- a/atari/src/fn_fuji/fuji_appkey_open_read.c
+++ b/atari/src/fn_fuji/fuji_appkey_open_read.c
@@ -41,7 +41,7 @@ bool fuji_read_appkey(uint8_t key_id, uint16_t *count, uint8_t *data)
 	open_data[4] = mode;
 	open_data[5] = 0; 		// reserved byte
 
-	copy_fuji_cmd_data(&t_fuji_open_appkey[0]);
+	copy_fuji_cmd_data(t_fuji_open_appkey);
 	OS.dcb.dbuf = open_data;
 	bus();
 	if (!fuji_success()) {
@@ -49,7 +49,7 @@ bool fuji_read_appkey(uint8_t key_id, uint16_t *count, uint8_t *data)
 		return false;
 	}
 
-	copy_fuji_cmd_data(&t_fuji_read_appkey[0]);
+	copy_fuji_cmd_data(t_fuji_read_appkey);
 	OS.dcb.dbuf = buffer;
 	OS.dcb.dbyt = buffer_size + 2; // add 2 for count bytes
 	bus();
diff --git a/atari/src/fn_fuji/fuji_appkey_open_write.c b/atari/src/fn_fuji/fuji_appkey_open_write.c
index 71bc3ef..f9c464c 100644
--- a/atari/src/fn_fuji/fuji_appkey_open_write.c
+++ b/atari/src/fn_fuji/fuji_appkey_open_write.c
@@ -34,12 +34,12 @@ bool fuji_write_appkey(uint8_t key_id, uint16_t count, uint8_t *data)
 	open_data[4] = 1;		// WRITE mode
 	open_data[5] = 0; 		// reserved byte
 
-	copy_fuji_cmd_data((uint8_t *) &t_fuji_open_appkey[0]);
+	copy_fuji_cmd_data(t_fuji_open_appkey);
 	OS.dcb.dbuf = open_data;
 	bus();
 	if (!fuji_success()) return false;
 
-	copy_fuji_cmd_data(&t_fuji_write_appkey[0]);
+	copy_fuji_cmd_data(t_fuji_write_appkey);
 	OS.dcb.dbuf = data;
 	OS.dcb.dbyt = keysize;		// we have to specify the 64/256/... value in dbyt
 	OS.dcb.daux = count;		// ... but the count can be less in daux to tell the FN how much of the buffer needs to be written
diff --git a/atari/src/include/fujinet-fuji-atari.h b/atari/src/include/fujinet-fuji-atari.h
index 6f40da8..cb12fa2 100644
--- a/atari/src/include/fujinet-fuji-atari.h
+++ b/atari/src/include/fujinet-fuji-atari.h
@@ -5,6 +5,6 @@
 #include <stdint.h>
 
 bool fuji_success();
-extern uint8_t *t_fuji_open_appkey[];
+extern uint8_t t_fuji_open_appkey[];
 
 #endif // FUJINET_FUJI_ATARI_H
\ No newline at end of file
diff --git a/makefiles/build.mk b/makefiles/build.mk
index 10b0338..9502a94 100644
--- a/makefiles/build.mk
+++ b/makefiles/build.mk
@@ -9,8 +9,9 @@ ALL_TASKS =
 DISK_TASKS =
 
 -include ./makefiles/os.mk
+-include ./makefiles/compiler.mk
 
-CC := cl65
+# CC := cl65
 
 SRCDIR := src
 BUILD_DIR := build
@@ -43,14 +44,14 @@ OBJECTS := $(OBJECTS:common/$(SRCDIR)/%=$(OBJDIR)/$(CURRENT_TARGET)/common/%)
 DEPENDS := $(OBJECTS:.o=.d)
 
 ASFLAGS += \
-	--asm-include-dir common/inc \
-	--asm-include-dir $(PLATFORM_SRC_DIR)/include \
-	--asm-include-dir .
+	$(INCS_ARG) common/inc \
+	$(INCS_ARG) $(PLATFORM_SRC_DIR)/include \
+	$(INCS_ARG) .
 
 CFLAGS += \
-	--include-dir common/inc \
-	--include-dir $(PLATFORM_SRC_DIR)/include \
-	--include-dir .
+	$(INCC_ARG) common/inc \
+	$(INCC_ARG) $(PLATFORM_SRC_DIR)/include \
+	$(INCC_ARG) .
 
 FN_NW_HEADER = fujinet-network.h
 FN_NW_INC = fujinet-network.inc
@@ -65,35 +66,12 @@ CHANGELOG = Changelog.md
 # allow for application specific config
 -include ./application.mk
 
-define _listing_
-  CFLAGS += --listing $$(@:.o=.lst)
-  ASFLAGS += --listing $$(@:.o=.lst)
-endef
-
-define _mapfile_
-  LDFLAGS += --mapfile $$@.map
-endef
-
-define _labelfile_
-  LDFLAGS += -Ln $$@.lbl
-endef
-
 .SUFFIXES:
-.PHONY: all clean release $(DISK_TASKS) $(BUILD_TASKS) $(PROGRAM_TGT) $(ALL_TASKS)
+.PHONY: all clean release $(PROGRAM_TGT) $(ALL_TASKS)
 
 all: $(ALL_TASKS) $(PROGRAM_TGT)
 
-STATEFILE := Makefile.options
 -include $(DEPENDS)
--include $(STATEFILE)
-
-ifeq ($(origin _OPTIONS_),file)
-OPTIONS = $(_OPTIONS_)
-$(eval $(OBJECTS): $(STATEFILE))
-endif
-
-# Transform the abstract OPTIONS to the actual cc65 options.
-$(foreach o,$(subst $(COMMA),$(SPACE),$(OPTIONS)),$(eval $(_$o_)))
 
 ifeq ($(BUILD_DIR),)
 BUILD_DIR := build
@@ -128,25 +106,44 @@ vpath %.c $(SRC_INC_DIRS)
 
 $(OBJDIR)/$(CURRENT_TARGET)/common/%.o: %.c | $(TARGETOBJDIR)
 	@$(call MKDIR,$(dir $@))
-	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(CFLAGS) -o $@ $<
+ifeq ($(CC),cl65)
+	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(CFLAGS) --listing $(@:.o=.lst) -Ln $@.lbl -o $@ $<
+else
+	$(CC) -c --deps $(CFLAGS) -o $@ $< 2>/dev/null
+endif
 
 $(OBJDIR)/$(CURRENT_TARGET)/%.o: %.c $(VERSION_FILE) | $(OBJDIR)
 	@$(call MKDIR,$(dir $@))
+ifeq ($(CC),cl65)
 	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(CFLAGS) -o $@ $<
+else
+	$(CC) -c --deps $(CFLAGS) -o $@ $< 2>/dev/null
+endif
 
 vpath %.s $(SRC_INC_DIRS)
 
-$(OBJDIR)/$(CURRENT_TARGET)/common/%.o: %.s | $(TARGETOBJDIR)
-	@$(call MKDIR,$(dir $@))
-	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(ASFLAGS) -o $@ $<
+## For now, no asm in common dirs... as it would be compiler specific
+# $(OBJDIR)/$(CURRENT_TARGET)/common/%.o: %.s | $(TARGETOBJDIR)
+# 	@$(call MKDIR,$(dir $@))
+# ifeq ($(CC),cl65)
+# 	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(ASFLAGS) -o $@ $<
+# else
+# endif
 
 $(OBJDIR)/$(CURRENT_TARGET)/%.o: %.s $(VERSION_FILE) | $(OBJDIR)
 	@$(call MKDIR,$(dir $@))
-	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(ASFLAGS) -o $@ $<
-
+ifeq ($(CC),cl65)
+	$(CC) -t $(CURRENT_TARGET) -c --create-dep $(@:.o=.d) $(ASFLAGS) --listing $(@:.o=.lst) -Ln $@.lbl -o $@ $<
+else
+	$(CC) -c --deps $(@:.o=.d) $(ASFLAGS) -o $@ $<
+endif
 
 $(BUILD_DIR)/$(PROGRAM_TGT): $(OBJECTS) | $(BUILD_DIR)
-	ar65 a $@ $(OBJECTS)
+ifeq ($(CC),cl65)
+	$(AR) a $@ $(OBJECTS)
+else
+	$(AR) $@ -a $(OBJECTS)
+endif
 
 $(PROGRAM_TGT): $(BUILD_DIR)/$(PROGRAM_TGT) | $(BUILD_DIR)
 
diff --git a/makefiles/common.mk b/makefiles/common.mk
index 0ceb18a..6d7a60e 100644
--- a/makefiles/common.mk
+++ b/makefiles/common.mk
@@ -1,4 +1,2 @@
 VERSION_FILE := version.txt
 VERSION_STRING := $(file < $(VERSION_FILE))
-
-CFLAGS += -Osir
\ No newline at end of file
diff --git a/makefiles/compiler-cc65.mk b/makefiles/compiler-cc65.mk
new file mode 100644
index 0000000..e9ef062
--- /dev/null
+++ b/makefiles/compiler-cc65.mk
@@ -0,0 +1,6 @@
+CC        := cl65
+AR        := ar65
+CFLAGS    := -Osir
+
+INCC_ARG  := --include-dir
+INCS_ARG  := --asm-include-dir
diff --git a/makefiles/compiler-cmoc.mk b/makefiles/compiler-cmoc.mk
new file mode 100644
index 0000000..21a6544
--- /dev/null
+++ b/makefiles/compiler-cmoc.mk
@@ -0,0 +1,6 @@
+CC        := cmoc
+AR        := lwar
+CFLAGS    := -O2
+
+INCC_ARG  := -I
+INCS_ARG  := -I
diff --git a/makefiles/compiler.mk b/makefiles/compiler.mk
new file mode 100644
index 0000000..7ece2e0
--- /dev/null
+++ b/makefiles/compiler.mk
@@ -0,0 +1,11 @@
+# sets the compiler and C args according to the target
+
+ifeq ($(CURRENT_TARGET),coco)
+
+-include makefiles/compiler-cmoc.mk
+
+else
+
+-include makefiles/compiler-cc65.mk
+
+endif
\ No newline at end of file
diff --git a/makefiles/os.mk b/makefiles/os.mk
index 0561de3..4033780 100644
--- a/makefiles/os.mk
+++ b/makefiles/os.mk
@@ -8,18 +8,21 @@ endif
 
 CURRENT_PLATFORM_apple2 := apple2
 CURRENT_PLATFORM_apple2enh := apple2
+
 CURRENT_PLATFORM_atari := atari
 CURRENT_PLATFORM_atarixl := atari
+
 CURRENT_PLATFORM_c64 := commodore
 CURRENT_PLATFORM_c128 := commodore
 CURRENT_PLATFORM_c16 := commodore
 CURRENT_PLATFORM_pet := commodore
 CURRENT_PLATFORM_plus4 := commodore
-#CURRENT_PLATFORM_x16 := commodore
 CURRENT_PLATFORM_cbm510 := commodore
 CURRENT_PLATFORM_cbm610 := commodore
 CURRENT_PLATFORM_vic20 := commodore
 
+CURRENT_PLATFORM_coco := coco
+
 CURRENT_PLATFORM = $(CURRENT_PLATFORM_$(CURRENT_TARGET))
 
 ifeq '$(findstring ;,$(PATH))' ';'