The firmware is definitely not open source, nor can it be modified in any way that I’m aware of. The processor is coated in black resin, so you can’t get to the pins. That makes reverse engineering much more difficult. There are some graphing calculators that can have custom firmware installed, but the only scientific calculators that I’m aware of with that functionality would be the SwissMicros line of calculators and the new HP 15C Collector’s Edition.
The firmware is definitely not open source, nor can it be modified in any way that I’m aware of. The processor is coated in black resin, so you can’t get to the pins. That makes reverse engineering much more difficult. There are some graphing calculators that can have custom firmware installed, but the only scientific calculators that I’m aware of with that functionality would be the SwissMicros line of calculators and the new HP 15C Collector’s Edition.