diff --git a/sys/dev/uart/uart.h b/sys/dev/uart/uart.h
--- a/sys/dev/uart/uart.h
+++ b/sys/dev/uart/uart.h
@@ -56,6 +56,11 @@
 	uint32_t ret;
 
 	switch (uart_regiowidth(bas)) {
+#if !defined(__i386__)
+	case 8:
+		ret = bus_space_read_8(bas->bst, bas->bsh, uart_regofs(bas, reg));
+		break;
+#endif
 	case 4:
 		ret = bus_space_read_4(bas->bst, bas->bsh, uart_regofs(bas, reg));
 		break;
@@ -71,10 +76,15 @@
 }
 
 static inline void
-uart_setreg(struct uart_bas *bas, int reg, int value)
+uart_setreg(struct uart_bas *bas, int reg, uint32_t value)
 {
 
 	switch (uart_regiowidth(bas)) {
+#if !defined(__i386__)
+	case 8:
+		bus_space_write_8(bas->bst, bas->bsh, uart_regofs(bas, reg), value);
+		break;
+#endif
 	case 4:
 		bus_space_write_4(bas->bst, bas->bsh, uart_regofs(bas, reg), value);
 		break;