I had the same problem - have 3 Humax boxes, 2 of which I have had no problems with the remotes. The 3rd is an Fvp-4000t and I have had problems with the home buttons from the get go.
I finally contacted Humax to ask where I could source another remote and this is the response I got -
Thank you for contacting Humax.
You can change the frequency of the remote control to make the units work independently. Please note that Youview models cannot have their frequency changed.
To do this,
Turn off any other Humax at the mains
On your remote, press and hold "0" and "OK" for roughly 8 -10 seconds
You will get a message on screen asking to press a number between 1 - 6
Press a number such as 3. The message will say remote now set to number 3 and disappear.
This will prevent your Humax units from conflicting. If the message says ''remote code change failed'' please retry the above instructions.
I tried this last night - and what a change. The buttons that before would not respond or would only respond if I repeatedly pressed them, worked on the first press. I am still slightly skeptical that it was such an easy fix, but have never had any point at which the remote did not cause problems. Last night was the first time everything worked well and responded at the first light press of the buttons.
Will keep you updated once I have had the next few days with it.