I was trying to update the firmware on a 2560 and installed v1.1.0 RC 8, after it finished downloading the LCD went to all boxes, the LCD speaker lets out a continuous squeal, and I am unable to connect to the printer. I was able to flash an older version of the firmware Marlin 1.0x. The squealing stopped after it fininshed, but the LCD is still all boxes and Repetier-host will not connect. I get a fatal error, fix error and use M999 to restart.