Thanks for your replies.

By the way on the subject of serial communication - known system calls can only do receiving or transmitting not both at the same time - correct me if you disagree - but it's something to take this into account for example by making corresponding loops in loops for those things respectively to wait to receive or send when necessary

Please share your thoughts or workarounds on this

Do you remember how or what exactly bricked your prizm? Was serial communication or something else running on it?

Regarding creation of g3a addins - should creating a file with not g3a extention work without any problems? And subsequently renaming it to g3a would normally work too provided the newly created g3a would not try to be placed on the main menu anywhere before the addin doing that renaming... So theoretically it should be possible to achieve all of the above.

But i may be missing crucial issues i'm not familiar with like will creating a file itself endanger parts of the calculator memory with the bootloader or anything important like that... Will receiving or serial communication going on before or after that endanger anything?

So it's just my thoughts/theories above and I would love to know how if any of those things actually work this way or not please - so please confirm or correct anything you agree or disagree with. Thanks in advance