Available flash commands

• cargo rriscv32iamc/cargo rrv32iamc: Use the riscv32iamc-unknown-none-elf target
• cargo rriscv32imc/cargo rrv32imc: Use the riscv32imc-unknown-none-elf target
• cargo rthumbv7em/cargo rtv7em: Use the thumbv7em-none-eabi target

Before flashing, write your board name to the environment variable PLATFORM or to a file named platform