Hello @Yuri_L and welcome to the community.
@Yuri_L wrote:
1. How does the STM32H562RI MCU burn firmware into the internal flash of the MCU? What Settings need to be made for hardware or software? Can it also be burned to an external flash? How is it operated?
To simply answering that question, you need a flashing tool for example STM32CubeProgrammer.
For an external flash you need a flash loader for that specific memory either you develop your self or you find something available and you modify it based on your needs. You may need to refer to this GitHub link. Refer also to this Mooc: How to create an external QSPI loader
@Yuri_L wrote:
2. Can the STM32H562RI MCU be boot from an external flash? How was it achieved?
You can't boot from an external flash. You need to boot from the internal memory, configure the external memory interface then jump to the external memory to execute an application.
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