https://www.bladox.com/products.php?lang=cz https://www.bladox.com/products.php?lang=cz, see "Turbo SIM" (the others' pictures may confuse the idea). It's an A

https://www.bladox.com/products.php?lang=cz https://www.bladox.com/products.php?lang=cz, see "Turbo SIM" (the others' pictures may confuse the idea). It's an ATMega128 which sits between the phone and SIM, intercepting all comms. It runs C code and provides an API which lets you read, manipulate or send any kind of SMS. Specifically, you can edit or prevent messages or any kind of SMS from reaching the SIM and thus your mobile operator's "secret" SIM apps. I used it at a previous job and can vouch for it. Doesn't look like they have versions for smaller SIMs, however.