Wireless Keyboard & Mouse KB3121Wp and MS3121Wt with USB Dongle

I have KB3121Wp MS3121Wt with USB Dongle.

How do I update firmware in all these three?

• Keyboard: Tried to update the firmware using Dell Peripheral Manager. The Keyboard says needs and update, but fails repeatdly (Agent lost). 
• Mouse: Doesn't say how to update firmware in the Mouse (if any).
• Dongle: Tried to update fimrware in the Dongle using firmware updater WR221, but that specific one said device not found. 

Any help will be appreciated.