OpenSprinkler › Forums › OpenSprinkler Unified Firmware › Can I upgrade a v1.2u board with 1.8.3 firmware? › Reply To: Can I upgrade a v1.2u board with 1.8.3 firmware? October 17, 2015 at 11:30 am #40535 RayKeymaster Unfortunately not — 1.2u uses a small microcontroller (ATmega328) which cannot fit any firmware beyond 1.8.3.
