diff --git a/flake.nix b/flake.nix
index c370991..56258e3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -9,6 +9,11 @@
     let 
       version = builtins.string 0 8 self.lastModifiedDate;
       supportedSystems = [ "x86_64-linux" "avr-none" ];
+      cflags = { mcu, chip_select, f_cpu }: ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Werror -Wstrict-prototypes -DF_CPU=${f_cpu} -std=gnu99 -D__${chip_select}__=1 -mmcu=${mcu}'';
+
+      attiny85 = { mcu = "attiny85"; chip_select = "AVR_ATtiny85"; f_cpu = "8000000"; };
+      atmega32u4 = { mcu = "atmega32u4"; chip_select = "AVR_ATmega32u4"; f_cpu = "8000000"; };
+      processor = atmega32u4;
     in rec
     {
       defaultPackage."x86_64-linux" = 
@@ -17,13 +22,27 @@
         in pkgs.symlinkJoin {
           name = "avr-monorepo";
           paths = [
-            packages."x86_64-linux"."flame"
-            packages."x86_64-linux"."prime-tx"
-            packages."x86_64-linux"."radio-rx"
+            (packages."x86_64-linux"."flame" processor)
+            (packages."x86_64-linux"."prime-tx" processor)
+            (packages."x86_64-linux"."radio-rx" processor)
           ];
         };
 
+        /*
+      packages."x86_64-linux"."base" =
+        { mcu, chip_select, f_cpu }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+          avr = pkgs.pkgsCross.avr.buildPackages;
+        in pkgs.stdenv.mkDerivation rec {
+          name = "base";
+          src = ./.;
+
+        };
+        */
+
       packages."x86_64-linux"."flame" =
+        { mcu, chip_select, f_cpu }:
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
           avr = pkgs.pkgsCross.avr.buildPackages;
@@ -31,10 +50,7 @@
           name = "flame";
           src = ./.;
 
-          MCU = "attiny85";
-          CHIP_SELECT = "AVR_ATtiny85";
-          F_CPU = "8000000";
-          CFLAGS = ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Werror -Wstrict-prototypes -DF_CPU=${F_CPU} -std=gnu99 -D__${CHIP_SELECT}__=1 -mmcu=${MCU}'';
+          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
 
           buildPhase = ''
             ${avr.gcc}/bin/avr-gcc ${CFLAGS} -I${src}/base -o base.o -c ${src}/base/base.c
@@ -50,6 +66,7 @@
         };
 
       packages."x86_64-linux"."prime-tx" =
+        { mcu, chip_select, f_cpu }:
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
           lib = pkgs.lib;
@@ -60,10 +77,7 @@
 
           includes = [ "base" "spi" "shift_register" "rfm69hcw" "display" ];
 
-          MCU = "atmega32u4";
-          CHIP_SELECT = "AVR_ATmega32u4";
-          F_CPU = "8000000";
-          CFLAGS = ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Werror -Wstrict-prototypes -DF_CPU=${F_CPU} -std=gnu99 -D__${CHIP_SELECT}__=1 -mmcu=${MCU} -DAVR=1'';
+          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = lib.concatStringsSep " " (map (dir: "-I${src}/${dir}") includes);
 
           buildPhase = ''
@@ -82,6 +96,7 @@
         };
 
       packages."x86_64-linux"."radio-rx" =
+        { mcu, chip_select, f_cpu }:
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
           lib = pkgs.lib;
@@ -92,10 +107,7 @@
 
           includes = [ "base" "spi" "shift_register" "rfm69hcw" "display" ];
 
-          MCU = "atmega32u4";
-          CHIP_SELECT = "AVR_ATmega32u4";
-          F_CPU = "8000000";
-          CFLAGS = ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Werror -Wstrict-prototypes -DF_CPU=${F_CPU} -std=gnu99 -D__${CHIP_SELECT}__=1 -mmcu=${MCU} -DAVR=1'';
+          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = lib.concatStringsSep " " (map (dir: "-I${src}/${dir}") includes);
 
           buildPhase = ''