diff --git a/Cargo.toml b/Cargo.toml
index 8c76ca3193..ab85545620 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "redox_syscall"
-version = "0.1.53"
+version = "0.1.54"
 description = "A Rust library to access raw Redox system calls"
 license = "MIT"
 authors = ["Jeremy Soller <jackpot51@gmail.com>"]
diff --git a/src/flag.rs b/src/flag.rs
index c519d0c123..6a03793b87 100644
--- a/src/flag.rs
+++ b/src/flag.rs
@@ -56,8 +56,9 @@ pub const O_SYMLINK: usize =    0x4000_0000;
 pub const O_NOFOLLOW: usize =   0x8000_0000;
 pub const O_ACCMODE: usize =    O_RDONLY | O_WRONLY | O_RDWR;
 
-pub const PHYSMAP_WRITE: usize = 1;
-pub const PHYSMAP_WRITE_COMBINE: usize = 2;
+pub const PHYSMAP_WRITE: usize = 0x0000_0001;
+pub const PHYSMAP_WRITE_COMBINE: usize = 0x0000_0002;
+pub const PHYSMAP_NO_CACHE: usize = 0x0000_0004;
 
 pub const PROT_NONE: usize = 0x0000_0000;
 pub const PROT_EXEC: usize = 0x0001_0000;