Continuing the discussion from Z axis was erratic…now I've got bigger problems:
I have the Arduino IDE version 1.6.11 installed on a Windows 7 machine. When compiling the Inventables fork (as of 8/31/2016) the following error occurs.
On the same machine I then run the Arduino IDE version 1.6.8 from a USB drive with the following results:
[Edit] I have compiled other projects with the 1.6.11 and the 1.6.8 versions without any change in code size.
Yep, That’s what I got!
Looks like you can duplicate the issue by downloading the most current IDE and then build. This for me was 2 bytes short of being over(Verification not upload. Not at my machine).
You can then go into board manager tools -> boards -> board manager. Anything >= 1.6.12 will ballon the size. Where as 1.6.11 is 30,072 bytes. So looks like an issue that needs to be reported to arduino.cc.
Ok so I have looked at the definition that gets downloaded with the boards and there are some differences.
You can download the 2 versions here
http://downloads.arduino.cc/cores/avr-1.6.11.tar.bz2
http://downloads.arduino.cc/cores/avr-1.6.12.tar.bz2
I have done a difference check on the 2 and the following changes
avr\ 2 is 1.6.12 and avr is 1.6.11
Files /Users/geoff/Downloads/avr/.DS_Store and /Users/geoff/Downloads/avr 2/.DS_Store differ Files /Users/geoff/Downloads/avr/bootloaders/.DS_Store and /Users/geoff/Downloads/avr 2/bootloaders/.DS_Store differ Files /Users/geoff/Downloads/avr/cores/.DS_Store and /Users/geoff/Downloads/avr 2/cores/.DS_Store differ Files /Users/geoff/Downloads/avr/cores/arduino/Print.cpp and /Users/geoff/Downloads/avr 2/cores/arduino/Print.cpp differ Files /Users/geoff/Downloads/avr/cores/arduino/Stream.h and /Users/geoff/Downloads/avr 2/cores/arduino/Stream.h differ Files /Users/geoff/Downloads/avr/cores/arduino/USBCore.cpp and /Users/geoff/Downloads/avr 2/cores/arduino/USBCore.cpp differ Files /Users/geoff/Downloads/avr/cores/arduino/USBCore.h and /Users/geoff/Downloads/avr 2/cores/arduino/USBCore.h differ Files /Users/geoff/Downloads/avr/cores/arduino/WString.cpp and /Users/geoff/Downloads/avr 2/cores/arduino/WString.cpp differ Files /Users/geoff/Downloads/avr/cores/arduino/WString.h and /Users/geoff/Downloads/avr 2/cores/arduino/WString.h differ Files /Users/geoff/Downloads/avr/libraries/SoftwareSerial/src/SoftwareSerial.h and /Users/geoff/Downloads/avr 2/libraries/SoftwareSerial/src/SoftwareSerial.h differ Files /Users/geoff/Downloads/avr/libraries/Wire/src/utility/twi.c and /Users/geoff/Downloads/avr 2/libraries/Wire/src/utility/twi.c differ Files /Users/geoff/Downloads/avr/platform.txt and /Users/geoff/Downloads/avr 2/platform.txt differ Files /Users/geoff/Downloads/avr/variants/ethernet/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/ethernet/pins_arduino.h differ Files /Users/geoff/Downloads/avr/variants/gemma/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/gemma/pins_arduino.h differ Files /Users/geoff/Downloads/avr/variants/leonardo/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/leonardo/pins_arduino.h differ Files /Users/geoff/Downloads/avr/variants/mega/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/mega/pins_arduino.h differ Files /Users/geoff/Downloads/avr/variants/robot_control/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/robot_control/pins_arduino.h differ Files /Users/geoff/Downloads/avr/variants/robot_motor/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/robot_motor/pins_arduino.h differ Files /Users/geoff/Downloads/avr/variants/standard/pins_arduino.h and /Users/geoff/Downloads/avr 2/variants/standard/pins_arduino.h differ
I need to get some of my own work done right now so if anyone wants to find what has changed enough to take 2,184 bytes go for it.
I down rev’d Arduino AVR Boards to 1.6.11 and it did fix the problem on my machine.
Thanks, Geoff
Opened issue at GitHub · Where software is built
Nice work guys, glad we got to the bottom of this (even more glad it isn’t a grbl issue).
Thanks for all your help, everyone! This will help us with future issues, and now we have a viable solution for customers.
Your efforts are much appreciated!
I hope I don’t discover any more problems for you guys! 
Sometimes I am an accident waiting to happen!!
I know this is a little late, but I compiled the inventables fork of GRBL on the 1.6.12 version (latest version) of the Arduino IDE on windows 10, 64 bit with no size issues.
I actually tested every version of grbl with no size issues.