Can STM32F429IGT6 and STM32F429IIT6 be used interchangeably?
STM32F429IIT6 has 2MB of flash memory. STM32F429IGT6 has only 1MB of flash memory. Otherwise they are the same. STM32F429IGT6 is cheaper.
https://www.st.com/en/microcontrollers-microprocessors/stm32f429-439.html