: Many embedded devices have a UART (serial) interface for low-level debugging. Tools like kwboot can send a boot image over this serial connection to revive a device.
: For developers, Jieli provides a tool called the JL-Download-Tool . This requires a specific .ufw firmware file and often a USB-to-TTL adapter to communicate with the chip's bootloader. br23uboot100
: Short for "Universal Bootloader," this is a tiny piece of permanent code embedded inside the chip's ROM. It is responsible for initializing the hardware and launching the controller's operational firmware. : Many embedded devices have a UART (serial)