diff --git a/src/arch/x86/include/bits/ns16550.h b/src/arch/x86/include/bits/ns16550.h
index cc2bd84c1..dbb1cd51c 100644
--- a/src/arch/x86/include/bits/ns16550.h
+++ b/src/arch/x86/include/bits/ns16550.h
@@ -23,7 +23,7 @@ static inline __attribute__ (( always_inline )) void
 ns16550_write ( struct ns16550_uart *ns16550, unsigned int address,
 		uint8_t data ) {
 
-	outb ( data, ( ns16550->base + address ) );
+	iowrite8 ( data, ( ns16550->base + address ) );
 }
 
 /**
@@ -36,7 +36,7 @@ ns16550_write ( struct ns16550_uart *ns16550, unsigned int address,
 static inline __attribute__ (( always_inline )) uint8_t
 ns16550_read ( struct ns16550_uart *ns16550, unsigned int address ) {
 
-	return inb ( ns16550->base + address );
+	return ioread8 ( ns16550->base + address );
 }
 
 /* Fixed ISA serial port base addresses */
diff --git a/src/include/bits/ns16550.h b/src/include/bits/ns16550.h
index e40b2a21b..45e3e978f 100644
--- a/src/include/bits/ns16550.h
+++ b/src/include/bits/ns16550.h
@@ -23,7 +23,7 @@ static inline __attribute__ (( always_inline )) void
 ns16550_write ( struct ns16550_uart *ns16550, unsigned int address,
 		uint8_t data ) {
 
-	writeb ( data, ( ns16550->base + ( address << ns16550->shift ) ) );
+	iowrite8 ( data, ( ns16550->base + ( address << ns16550->shift ) ) );
 }
 
 /**
@@ -36,7 +36,7 @@ ns16550_write ( struct ns16550_uart *ns16550, unsigned int address,
 static inline __attribute__ (( always_inline )) uint8_t
 ns16550_read ( struct ns16550_uart *ns16550, unsigned int address ) {
 
-	return readb ( ns16550->base + ( address << ns16550->shift ) );
+	return ioread8 ( ns16550->base + ( address << ns16550->shift ) );
 }
 
 #endif /* _BITS_NS16550_H */