I was trying to install a custom applet on sysmoUSIM-SJS1 SIM cards. Following  the guide present here and using shadysim I was not able to do that ( it gives me an error related to the fact it doesn't receive any status word back after sending an APDU, I think it's a bug but we can discuss about that later). I ended up using Global Platform Pro to install it but it only loads the applet on the card as a module of another package and doesn't make it selectable.

I also tried to upload the applet suggested by you in the guide, but I got same result.

Is it something related to the sim card? Should I buy the SJA2 version? Can you help me?

Thanks,

Matteo