AS Java licenses installed via telnet are invalid

[#1]

Dear experts,

we have a Java system, on which the licensing area cannot be shown in NWA.
Therefore, I am trying to install the license via telnet as per SAP note 2444530.
However, when I test the license with the list_licenses command, they all are
showing invalid!

I was wondering what is wrong and wanted to double-check if I've got the correct
hardware key by saplicense -get

So, looking for a solution, I quickly found the following blog:

https://blogs.sap.com/2016/09/06/as-java-license-key-installation-using-telnet/

It advises to use the mshardwareid command, nevertheless when I try to launch
it, it simply says:

Can't find command 'mshardwareid'.

I started thinking if it is not just for windows, as it starts with ms. Then I wanted to
obtain a list of the commands, trying ? or help, unfortunately none of this works!

Any further ideas please ? I'm really stuck here! Thanks a lot!