diff --git a/kernel/Makefile b/kernel/Makefile
index b8adb2db..9ed8b9d7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -318,7 +318,7 @@ ifeq ($(board), u540)
 .PHONY:
 install: $(kernel_img)
 	@$(objcopy) -S -O binary --change-addresses -0x80000000 $< $(build_path)/bin
-	@sudo sh ../tools/u540/mkimg.sh $(build_path)/bin $(build_path)/sd.img
+	@../tools/u540/mkimg.sh $(build_path)/bin $(build_path)/sd.img
 endif
 
 .PHONY:
diff --git a/kernel/src/arch/riscv32/board/u540/mod.rs b/kernel/src/arch/riscv32/board/u540/mod.rs
new file mode 100644
index 00000000..cc538744
--- /dev/null
+++ b/kernel/src/arch/riscv32/board/u540/mod.rs
@@ -0,0 +1,18 @@
+use super::consts::KERNEL_OFFSET;
+
+/// Mask all external interrupt except serial.
+pub unsafe fn init_external_interrupt() {
+    const HART1_S_MODE_INTERRUPT_ENABLES: *mut u64 = (KERNEL_OFFSET + 0x0C00_2100) as *mut u64;
+    const SERIAL: u64 = 4;
+    HART1_S_MODE_INTERRUPT_ENABLES.write(1 << SERIAL);
+}
+
+/// Claim and complete external interrupt by reading and writing to
+/// PLIC Interrupt Claim/Complete Register.
+pub unsafe fn handle_external_interrupt() {
+    const HART1_S_MODE_INTERRUPT_CLAIM_COMPLETE: *mut u32 = (KERNEL_OFFSET + 0x0C20_2004) as *mut u32;
+    // claim
+    let source = HART1_S_MODE_INTERRUPT_CLAIM_COMPLETE.read();
+    // complete
+    HART1_S_MODE_INTERRUPT_CLAIM_COMPLETE.write(source);
+}
\ No newline at end of file
diff --git a/kernel/src/arch/riscv32/interrupt.rs b/kernel/src/arch/riscv32/interrupt.rs
index 17a0d7d2..2d952be7 100644
--- a/kernel/src/arch/riscv32/interrupt.rs
+++ b/kernel/src/arch/riscv32/interrupt.rs
@@ -34,14 +34,16 @@ pub fn init() {
         xtvec::write(trap_entry as usize, xtvec::TrapMode::Direct);
         // Enable IPI
         sie::set_ssoft();
-        // Enable serial interrupt
-        #[cfg(feature = "m_mode")]
-        mie::set_mext();
-        #[cfg(not(feature = "m_mode"))]
-        sie::set_sext();
-        // NOTE: In M-mode: mie.MSIE is set by BBL.
-        //                  mie.MEIE can not be set in QEMU v3.0
-        //                  (seems like a bug)
+        // Enable external interrupt
+        if super::cpu::id() == super::BOOT_HART_ID {
+            #[cfg(feature = "m_mode")]
+            mie::set_mext();
+            #[cfg(not(feature = "m_mode"))]
+            sie::set_sext();
+            // NOTE: In M-mode: mie.MSIE is set by BBL.
+            //                  mie.MEIE can not be set in QEMU v3.0
+            //                  (seems like a bug)
+        }
     }
     info!("interrupt: init end");
 }
@@ -130,6 +132,9 @@ fn sbi(tf: &mut TrapFrame) {
 }
 
 fn external() {
+    #[cfg(feature = "board_u540")]
+    unsafe { super::board::handle_external_interrupt(); }
+
     // true means handled, false otherwise
     let handlers = [try_process_serial, try_process_drivers];
     for handler in handlers.iter() {
diff --git a/kernel/src/arch/riscv32/memory.rs b/kernel/src/arch/riscv32/memory.rs
index 48e91d46..21a84822 100644
--- a/kernel/src/arch/riscv32/memory.rs
+++ b/kernel/src/arch/riscv32/memory.rs
@@ -79,6 +79,10 @@ fn remap_the_kernel(dtb: usize) {
     ms.push(bootstack as usize, bootstacktop as usize, MemoryAttr::default(), Linear::new(offset), "stack");
     ms.push(sbss as usize, ebss as usize, MemoryAttr::default(), Linear::new(offset), "bss");
     ms.push(dtb, dtb + super::consts::MAX_DTB_SIZE, MemoryAttr::default().readonly(), Linear::new(offset), "dts");
+    // map PLIC for HiFiveU
+    let offset = -(KERNEL_OFFSET as isize);
+    ms.push(KERNEL_OFFSET + 0x0C00_2000, KERNEL_OFFSET + 0x0C00_2000 + PAGE_SIZE, MemoryAttr::default(), Linear::new(offset), "plic0");
+    ms.push(KERNEL_OFFSET + 0x0C20_2000, KERNEL_OFFSET + 0x0C20_2000 + PAGE_SIZE, MemoryAttr::default(), Linear::new(offset), "plic1");
     unsafe { ms.activate(); }
     unsafe { SATP = ms.token(); }
     mem::forget(ms);
diff --git a/kernel/src/arch/riscv32/mod.rs b/kernel/src/arch/riscv32/mod.rs
index 32fe8976..4b42ad0a 100644
--- a/kernel/src/arch/riscv32/mod.rs
+++ b/kernel/src/arch/riscv32/mod.rs
@@ -7,6 +7,9 @@ pub mod compiler_rt;
 pub mod consts;
 pub mod cpu;
 pub mod syscall;
+#[cfg(feature = "board_u540")]
+#[path = "board/u540/mod.rs"]
+mod board;
 mod sbi;
 
 use log::*;
@@ -36,6 +39,8 @@ pub extern fn rust_main(hartid: usize, dtb: usize, hart_mask: usize, functions:
     // FIXME: init driver on u540
     #[cfg(not(feature = "board_u540"))]
     crate::drivers::init(dtb);
+    #[cfg(feature = "board_u540")]
+    unsafe { board::init_external_interrupt(); }
     crate::process::init();
 
     unsafe { cpu::start_others(hart_mask); }
diff --git a/riscv-pk b/riscv-pk
index 2829915e..405ea59d 160000
--- a/riscv-pk
+++ b/riscv-pk
@@ -1 +1 @@
-Subproject commit 2829915ea12fba2e5fd4db2879e23311043a55b4
+Subproject commit 405ea59dd7dd2762c5883822f21d9995bea32b0c
diff --git a/tools/u540/mkimg.sh b/tools/u540/mkimg.sh
old mode 100644
new mode 100755