diff --git a/repos/base/include/drivers/uart/x86_pc.h b/repos/base/include/drivers/uart/x86_pc.h
index 3f509144ce..67e9cfa8fe 100644
--- a/repos/base/include/drivers/uart/x86_pc.h
+++ b/repos/base/include/drivers/uart/x86_pc.h
@@ -17,6 +17,7 @@
 
 /* Genode includes */
 #include <base/stdint.h>
+#include <cpu/memory_barrier.h>
 
 namespace Genode { class X86_uart; }
 
@@ -87,7 +88,7 @@ class Genode::X86_uart
 				DLHI = (uint16_t)(_port + 1);
 
 			_outb(LCR, 0x80);  /* select bank 1 */
-			for (volatile int i = 10000000; i--; );
+			for (int i = 10000000; i; --i) memory_barrier();
 			_outb(DLLO, (uint8_t)((115200/_baud_rate) >> 0));
 			_outb(DLHI, (uint8_t)((115200/_baud_rate) >> 8));
 			_outb(LCR, 0x03);  /* set 8,N,1 */
diff --git a/repos/os/src/drivers/uart/spec/x86/uart_driver.h b/repos/os/src/drivers/uart/spec/x86/uart_driver.h
index d62fc2315c..fc6638f0f1 100644
--- a/repos/os/src/drivers/uart/spec/x86/uart_driver.h
+++ b/repos/os/src/drivers/uart/spec/x86/uart_driver.h
@@ -18,6 +18,7 @@
 /* Genode includes */
 #include <base/env.h>
 #include <io_port_session/connection.h>
+#include <cpu/memory_barrier.h>
 
 enum { UARTS_NUM = 4 }; /* needed by base class definitions */
 
@@ -87,7 +88,7 @@ class Uart::Driver : public Uart::Driver_base
 		void _init_comport(size_t baud)
 		{
 			_outb<LCR>(0x80u);  /* select bank 1 */
-			for (volatile int i = 10000000; i--; );
+			for (int i = 10000000; i; i--) memory_barrier();
 			_outb<DLLO>(((115200/baud) >> 0) && 0xff);
 			_outb<DLHI>(((115200/baud) >> 8) && 0xff);
 			_outb<LCR>(0x03u);  /* set 8,N,1 */