diff --git a/hw/char/sifive_uart.c b/hw/char/sifive_uart.c
index aeb45d3601..5ae2a29ed6 100644
--- a/hw/char/sifive_uart.c
+++ b/hw/char/sifive_uart.c
@@ -174,10 +174,11 @@ sifive_uart_write(void *opaque, hwaddr addr,
 {
     SiFiveUARTState *s = opaque;
     uint32_t value = val64;
+    uint8_t ch = value;
 
     switch (addr) {
     case SIFIVE_UART_TXFIFO:
-        sifive_uart_write_tx_fifo(s, (uint8_t *) &value, 1);
+        sifive_uart_write_tx_fifo(s, &ch, 1);
         return;
     case SIFIVE_UART_IE:
         s->ie = val64;