diff --git a/src/arch/x86_64/device/serial.rs b/src/arch/x86_64/device/serial.rs
index a9548d5fe830acc9fe7ab1b32bbe65a83eb13d82..1f3e18cfacb7ed37d9d79b34b9fb45100f7a76b8 100644
--- a/src/arch/x86_64/device/serial.rs
+++ b/src/arch/x86_64/device/serial.rs
@@ -13,8 +13,6 @@ pub static LPSS: Mutex<Option<&'static mut SerialPort<Mmio<u32>>>> = Mutex::new(
 pub unsafe fn init() {
     COM1.lock().init();
     COM2.lock().init();
-    COM3.lock().init();
-    COM4.lock().init();
 
     #[cfg(feature = "lpss_debug")]
     {
diff --git a/src/arch/x86_64/interrupt/irq.rs b/src/arch/x86_64/interrupt/irq.rs
index ccd505c7cc29d9a0079c95d4fc90940790ed7da9..8c755baa31dd4974fab94ad9c74786c6f2806bf0 100644
--- a/src/arch/x86_64/interrupt/irq.rs
+++ b/src/arch/x86_64/interrupt/irq.rs
@@ -2,7 +2,7 @@ use core::sync::atomic::{AtomicUsize, Ordering};
 
 use crate::context::timeout;
 use crate::device::pic;
-use crate::device::serial::{COM1, COM2, COM3, COM4};
+use crate::device::serial::{COM1, COM2};
 use crate::ipi::{ipi, IpiKind, IpiTarget};
 use crate::scheme::debug::debug_input;
 use crate::{context, ptrace, time};
@@ -78,9 +78,6 @@ interrupt!(com2, {
     while let Some(c) = COM2.lock().receive() {
         debug_input(c);
     }
-    while let Some(c) = COM4.lock().receive() {
-        debug_input(c);
-    }
     pic::MASTER.ack();
 });
 
@@ -88,9 +85,6 @@ interrupt!(com1, {
     while let Some(c) = COM1.lock().receive() {
         debug_input(c);
     }
-    while let Some(c) = COM3.lock().receive() {
-        debug_input(c);
-    }
     pic::MASTER.ack();
 });