A QRSS MEPT.
If you are homebrewing OpenBeacon and are burning a copy of the firmware .hex file on your own ATtiny85, then be sure to use the following fuse settings in order for the microcontroller to work correctly:
Low: 0xE1
High: 0x5D
Ext: 0xFF
If you are using a *nix machine, I've included a handy script to burn the firmware and set the fuses called burn_firmware.sh in the firmware/Release folder.