diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index 0aa06a8703..721d163187 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -132,7 +132,7 @@ pub fn os_open(vm: &VirtualMachine, args: PyFuncArgs) -> PyResult {
 fn _set_file_model(flags: &PyObjectRef) -> OpenOptions {
     let flags = objint::get_value(flags).to_i32().unwrap();
     let mut options = OpenOptions::new();
-    options.read(flags & libc::O_RDONLY != 0);
+    options.read(flags == libc::O_RDONLY);
     options.write(flags & libc::O_WRONLY != 0);
     options.append(flags & libc::O_APPEND != 0);
     options.custom_flags(flags);
@@ -143,7 +143,7 @@ fn _set_file_model(flags: &PyObjectRef) -> OpenOptions {
 fn _set_file_model(flags: &PyObjectRef) -> OpenOptions {
     let flags = objint::get_value(flags).to_u32().unwrap();
     let mut options = OpenOptions::new();
-    options.read((flags as i32) & libc::O_RDONLY != libc::O_RDONLY);
+    options.read((flags as i32) == libc::O_RDONLY);
     options.write((flags as i32) & libc::O_WRONLY != 0);
     options.append((flags as i32) & libc::O_APPEND != 0);
     options.custom_flags(flags);