Overclocking: You have to edit /config/asic-freq.config, not /etc/asic-freq.config
After you make your edits, go to the miner configuration page and click save & apply to restart cgminer without rebooting.

Files may or may not revert to their original state after a reboot.

Does anyone know what values to use for option 'freq_value', option 'chip_freq', and option 'timeout' if you want a 225M clock?