firebox disable, gcc flag for smaller binary

platformio.ini

@@ -50,17 +50,18 @@ monitor_speed = 115200
 monitor_echo = yes
 build_flags = -std=c++17
 
-[env:samc21-firebox]
-platform = atmelsam
-board = firebox
-framework = arduino
-upload_protocol = atmel-ice
-lib_deps = 
-	${env.lib_deps}
-	SparkFun External EEPROM Arduino Library
-monitor_speed = 115200
-monitor_echo = yes
-build_flags = -std=c++17
+; Firebox disabled for now
+; [env:samc21-firebox]
+; platform = atmelsam
+; board = firebox
+; framework = arduino
+; upload_protocol = atmel-ice
+; lib_deps = 
+;	${env.lib_deps}
+;	SparkFun External EEPROM Arduino Library
+;monitor_speed = 115200
+;monitor_echo = yes
+;build_flags = -std=c++17
 
 [env:mega2560-debug]
 platform = atmelavr
@@ -108,6 +109,10 @@ lib_deps =
 	SPI
 monitor_speed = 115200
 monitor_echo = yes
+; Example, but v12 does generate bigger binaries
+; platform_packages = toolchain-atmelavr@symlink:///opt/avr-gcc-12.1.0-x64-linux
+; Should make binaries smaller
+build_flags = -mcall-prologues
 
 [env:mega328]
 platform = atmelavr
@@ -155,6 +160,8 @@ lib_deps =
 	SPI
 monitor_speed = 115200
 monitor_echo = yes
+; Should make binaries smaller
+build_flags = -mcall-prologues
 
 [env:nano]
 platform = atmelavr