# 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|--listen_port]}} {{4500}}` - Connect to GDB server within `gdb`: `target extended-remote {{localhost}}:{{4500}}` - Write firmware to device: `load {{firmware.elf}}`