I've download the TivaWare_C_Series-2.1.2.111 and compile the example to EK-LM4C1294XL,then I download the boot_serial.bin(bootloader) to my board using JTAG.After this be done,I still cann't use the UART to download boot_demo1 whatever the config is.Can someone help me? Or who can give me a new boot_serial.bin and boot_demo1.bin .Or who can tell me what step am I wrong?Thanks very much!