# st-util > Run GDB (GNU Debugger) server to interact with STM32 ARM Cortex microcontoller. > More information: . - Run GDB server on port 4500: `st-util -p {{4500}}` - Connect to GDB server: `(gdb) target extended-remote {{localhost}}:{{4500}}` - Write firmware to device: `(gdb) load {{firmware.elf}}`