diff --git a/kernel/src/objects/frame.rs b/kernel/src/objects/frame.rs
index 69c68b3..2532f44 100644
--- a/kernel/src/objects/frame.rs
+++ b/kernel/src/objects/frame.rs
@@ -52,10 +52,8 @@ impl<'a> FrameCap<'a> {
     const VM_RIGHT_MASK: usize = MASK!(Self::VM_RIGHT_BITS);
     const VM_RIGHT_OFFSET: usize = 0;
 
-    pub fn mint(ptr: PhysAddr, size: usize, attr: MapAttr, is_device: bool) -> RawCap {
-        let size_bits = size.ilog2() as usize;
-        debug_assert!(size_bits <= FrameCap::FRAME_SIZE_BITS);
-        assert!(size >= PAGE_SIZE);
+    pub fn mint(ptr: PhysAddr, size_bits: usize, attr: MapAttr, is_device: bool) -> RawCap {
+        debug_assert!(size_bits <= MASK!(Self::FRAME_SIZE_BITS)); // 1<<63
 
         let arg0 = 0
             | ((attr.bits() & Self::VM_RIGHT_MASK) << Self::VM_RIGHT_OFFSET)
diff --git a/kernel/src/objects/untyped.rs b/kernel/src/objects/untyped.rs
index 8ff8709..ebbae98 100644
--- a/kernel/src/objects/untyped.rs
+++ b/kernel/src/objects/untyped.rs
@@ -1,7 +1,8 @@
 use super::cap::RawCap;
 use super::cnode::{CNodeCap, CNodeObject};
 use super::null::NullCap;
-use super::{Cap, KernelObject, TableCap, TcbCap};
+use super::{Cap, FrameCap, KernelObject, TableCap, TcbCap};
+use crate::vspace::MapAttr;
 use core::fmt::Debug;
 use uapi::cap::ObjectType;
 use uapi::error::{SysError, SysResult};
@@ -107,7 +108,6 @@ impl UntypedCap<'_> {
 
         // Check whether we are handling device memory
         if self.is_device() && obj_type != ObjectType::Frame && obj_type != ObjectType::Untyped {
-            // TODO: we might split frame into tera, giga, mega, kilo...
             return Err(SysError::InvalidArgument);
         }
 
@@ -119,6 +119,7 @@ impl UntypedCap<'_> {
                 ObjectType::CNode => CNodeCap::mint(user_obj_bits, 0, 0, addr),
                 ObjectType::TCB => TcbCap::mint(addr),
                 ObjectType::Table => TableCap::mint(addr),
+                ObjectType::Frame => FrameCap::mint(addr, user_obj_bits, MapAttr::empty(), self.is_device()),
                 // TODO: other object types
                 _ => return Err(SysError::InvalidArgument),
             };