I have updated Mighty 1284P to work with Arduino IDE 1.5+ https://github.com/per1234/mighty-1284p/tree/IDE-1.5.x-compatibility. I had to update the patched GSM library because the previous patched version doesn't work with 1.5+ but I don't have the GSM hardware to test it. Does anyone have an ATmega1284/644 and the GSM hardware that can try it out and let me know if it works: https://github.com/per1234/mighty-1284p/tree/IDE-1.5.x-compatibility/patched-libs/official/IDE1.5.x-Compatible/GSM
Thanks, Per