Hi Harald,
I've never tried the "-delete" option for any of the ISIM/USIM applications, but it does look rather easy to try, if you are interested in that kind of thing.
Right now my curiosity in this area isn't strong enough to invest the time into installing and learning the necessary tools, but I may indeed try it one day.
Please note, once you deleted it, there is likely no way to recover, as sysmocom cannot distribute third-party card applications in installable form.
Yes, I realize that I may blow the card - but I got a pack of 10 of them for no purpose other than experiments, so... And because they are your current standard webshop product, I could always buy another pack if need arises.
I disagree. This was a deliberate design decision for the SJA2 cards, in order to ensure maximum flexibility. If you link/share those files, then all applications must always share the same key material and algorithm.
Then the actual linked vs. separate arrangement on the card should be documented - meaning explicitly document what is shared/linked vs. what is separate per SIM/USIM/ISIM. Your manual does not explicitly say one way or the other, and the comments in sysmo_isim_sja2.py make it sound like it is some kind of unknown (which made me think of reverse eng) whether the files are separate or linked.
M~