Hi
I’m sorry but I don’t have the answer for you, as I don’t have a Humax HD box, only 9200t and HD cable PVRs. However could you confirm that your remote uses 4 digit codes and that you have tried the ones for Humax in the manual (link to manual in the post linked here) (you need to be logged in to view or download)
There may not be a code in the remotes memory as that would effectively be 2 PVRs which on most pre-programmable remotes would require reprogramming one of the device keys to a different device type prior to inputting the code. You would need a fully programmable universal remote for that such as the One For All Xsight or Logitech Harmony range, or a learning remote.
Of course ISTBC