diff --git a/bootloader/rustsbi-k210.bin b/bootloader/rustsbi-k210.bin
index 27987d68..c53ed1fc 100755
Binary files a/bootloader/rustsbi-k210.bin and b/bootloader/rustsbi-k210.bin differ
diff --git a/bootloader/rustsbi-qemu.bin b/bootloader/rustsbi-qemu.bin
index 0e61b8ea..ddbf336a 100755
Binary files a/bootloader/rustsbi-qemu.bin and b/bootloader/rustsbi-qemu.bin differ
diff --git a/rust-toolchain b/rust-toolchain
index bf867e0a..1c5af266 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly
+nightly-2021-08-25
diff --git a/user/src/lib.rs b/user/src/lib.rs
index 0d4e44a7..902c5421 100644
--- a/user/src/lib.rs
+++ b/user/src/lib.rs
@@ -1,5 +1,5 @@
 #![no_std]
-#![feature(llvm_asm)]
+#![feature(asm)]
 #![feature(linkage)]
 #![feature(panic_info_message)]
 
diff --git a/user/src/syscall.rs b/user/src/syscall.rs
index 1b23a48a..ed3d16aa 100644
--- a/user/src/syscall.rs
+++ b/user/src/syscall.rs
@@ -6,11 +6,12 @@ const SYSCALL_GET_TIME: usize = 169;
 fn syscall(id: usize, args: [usize; 3]) -> isize {
     let mut ret: isize;
     unsafe {
-        llvm_asm!("ecall"
-            : "={x10}" (ret)
-            : "{x10}" (args[0]), "{x11}" (args[1]), "{x12}" (args[2]), "{x17}" (id)
-            : "memory"
-            : "volatile"
+        asm!(
+            "ecall",
+            inlateout("x10") args[0] => ret,
+            in("x11") args[1],
+            in("x12") args[2],
+            in("x17") id
         );
     }
     ret