Пробовал - не помогло. К тому же в stm32f4xx_hal_uart.h пишут что
для TX (Gstate) надо использовать HAL_UART_STATE_BUSY_TX Но все
равно спасибо за совет :) HAL_UART_STATE_BUSY_TX = 0x21U, /*!< Data Transmission process is ongoing
Value is allowed for gState only */
HAL_UART_STATE_BUSY_RX = 0x22U, /*!< Data Reception process is ongoing
Value is allowed for RxState only */
HAL_UART_STATE_BUSY_TX_RX = 0x23U, /*!< Data Transmission and Reception process is ongoing
Not to be used for neither gState nor RxState.