diff --git a/Cargo.lock b/Cargo.lock
index 27c3298c..034bf3d8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -33,7 +33,7 @@ dependencies = [
  "spin",
  "uart_16550",
  "volatile",
- "x86_64",
+ "x86_64 0.11.0",
 ]
 
 [[package]]
@@ -188,7 +188,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d44b0f30cb82b0fbc15b78ade1064226529ad52028bc8cb8accb98ff6f3d7131"
 dependencies = [
  "bitflags",
- "x86_64",
+ "x86_64 0.9.6",
 ]
 
 [[package]]
@@ -206,3 +206,13 @@ dependencies = [
  "bit_field",
  "bitflags",
 ]
+
+[[package]]
+name = "x86_64"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "365de37eb7c6da582cbb510dd0f3f1235d24ff6309a8a96e8a9909cc9bfd608f"
+dependencies = [
+ "bit_field",
+ "bitflags",
+]
diff --git a/Cargo.toml b/Cargo.toml
index 08d6ab3c..f895256a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,7 @@ harness = false
 bootloader = { version = "0.9.3", features = ["map_physical_memory"]}
 volatile = "0.2.6"
 spin = "0.5.2"
-x86_64 = "0.9.6"
+x86_64 = "0.11.0"
 uart_16550 = "0.2.0"
 pic8259_simple = "0.1.1"
 pc-keyboard = "0.5.0"
diff --git a/src/allocator.rs b/src/allocator.rs
index dce05a62..60444675 100644
--- a/src/allocator.rs
+++ b/src/allocator.rs
@@ -35,7 +35,7 @@ pub fn init_heap(
             .allocate_frame()
             .ok_or(MapToError::FrameAllocationFailed)?;
         let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
-        mapper.map_to(page, frame, flags, frame_allocator)?.flush();
+        unsafe { mapper.map_to(page, frame, flags, frame_allocator)?.flush() };
     }
 
     unsafe {
diff --git a/src/memory.rs b/src/memory.rs
index e9380203..c64b72d4 100644
--- a/src/memory.rs
+++ b/src/memory.rs
@@ -2,7 +2,6 @@ use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
 use x86_64::{
     structures::paging::{
         FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
-        UnusedPhysFrame,
     },
     PhysAddr, VirtAddr,
 };
@@ -45,11 +44,12 @@ pub fn create_example_mapping(
     use x86_64::structures::paging::PageTableFlags as Flags;
 
     let frame = PhysFrame::containing_address(PhysAddr::new(0xb8000));
-    // FIXME: ONLY FOR TEMPORARY TESTING
-    let unused_frame = unsafe { UnusedPhysFrame::new(frame) };
     let flags = Flags::PRESENT | Flags::WRITABLE;
 
-    let map_to_result = mapper.map_to(page, unused_frame, flags, frame_allocator);
+    let map_to_result = unsafe {
+        // FIXME: this is not safe, we do it only for testing
+        mapper.map_to(page, frame, flags, frame_allocator)
+    };
     map_to_result.expect("map_to failed").flush();
 }
 
@@ -57,7 +57,7 @@ pub fn create_example_mapping(
 pub struct EmptyFrameAllocator;
 
 unsafe impl FrameAllocator<Size4KiB> for EmptyFrameAllocator {
-    fn allocate_frame(&mut self) -> Option<UnusedPhysFrame> {
+    fn allocate_frame(&mut self) -> Option<PhysFrame> {
         None
     }
 }
@@ -82,7 +82,7 @@ impl BootInfoFrameAllocator {
     }
 
     /// Returns an iterator over the usable frames specified in the memory map.
-    fn usable_frames(&self) -> impl Iterator<Item = UnusedPhysFrame> {
+    fn usable_frames(&self) -> impl Iterator<Item = PhysFrame> {
         // get usable regions from memory map
         let regions = self.memory_map.iter();
         let usable_regions = regions.filter(|r| r.region_type == MemoryRegionType::Usable);
@@ -91,14 +91,12 @@ impl BootInfoFrameAllocator {
         // transform to an iterator of frame start addresses
         let frame_addresses = addr_ranges.flat_map(|r| r.step_by(4096));
         // create `PhysFrame` types from the start addresses
-        let frames = frame_addresses.map(|addr| PhysFrame::containing_address(PhysAddr::new(addr)));
-        // we know that the frames are really unused
-        frames.map(|f| unsafe { UnusedPhysFrame::new(f) })
+        frame_addresses.map(|addr| PhysFrame::containing_address(PhysAddr::new(addr)))
     }
 }
 
 unsafe impl FrameAllocator<Size4KiB> for BootInfoFrameAllocator {
-    fn allocate_frame(&mut self) -> Option<UnusedPhysFrame> {
+    fn allocate_frame(&mut self) -> Option<PhysFrame> {
         let frame = self.usable_frames().nth(self.next);
         self.next += 1;
         frame