This info may be useful for those people who lost the parental lock of their satellite receiver HUMAX 5410z - 5400z (lol come on!).
1) Go to the STB status in the Main menu: installation -> ok -> status -> ok -> stb status -> ok
2) Press the following sequence of keys: Red -> Green -> Yellow -> Blue -> White -> 0
3) The pin code is automatically reset to factory default (0000)