Please log into the Web Control Panel and go to the tab called "Mining Status."
If the status page looks like this, please check the value listed in the "Frequency" if it shows, 200 instead of 350.
This indicates, you may have the Antminer S4 firmware instead of S5 firmware. Please download the S5 firmware from here.
Go to the "System" tab then to the "upgrade" tab.
Please select the above downloaded file, then make sure the "Keep settings" check box is UNCHECKED.
Click "Flash Image" and wait for a few minutes to upgrade.
After the successful upgrade, please power off the S5 and power it back on. The ASIC Frequency value should change to "350"
*This process will reset all of your network values and mining pool settings. Please readjust the setting to your information.