Browse Hydrotab’s site, visit Downloads on Firmware section, download and install DfuSe demo software (DfuSe_Demo_V3.0.4_Setup.exe). The program is compatible to the following operational systems: Windows 98SE, 2000, XP, Vista, 7, 8.x (x86 & x64 Windows platforms).
Run the DfuSe software and choose the latest Firmware through the downloaded files by going to MyComputer>>Downloads.
Remove I/O (electrical supply).
Connect the 4DHC (via USB port to micro USB) to the computer by holding the menu button (I/O) of 4DHC Controller, until the Upgrade button become clickable on DfuSe software window.
Click at the Upgrade button, press “Yes” on the question “Continue however?” wait till the lower bar of the software appears the message 'Upgrade successful!’. Click at Quit button, your 4DHC is upgraded.