diff --git a/lib/mammoth/include/mammoth/memory_region.h b/lib/mammoth/include/mammoth/memory_region.h
index a74b36f..6728f55 100644
--- a/lib/mammoth/include/mammoth/memory_region.h
+++ b/lib/mammoth/include/mammoth/memory_region.h
@@ -51,7 +51,6 @@ class OwnedMemoryRegion {
 
   static OwnedMemoryRegion FromCapability(z_cap_t vmmo_cap);
 
-  uint64_t paddr() { return paddr_; }
   uint64_t vaddr() { return vaddr_; }
   uint64_t size() { return size_; }
 
@@ -61,11 +60,9 @@ class OwnedMemoryRegion {
   explicit operator bool() { return vmmo_cap_ != 0; }
 
  private:
-  OwnedMemoryRegion(uint64_t vmmo_cap, uint64_t paddr, uint64_t vaddr,
-                    uint64_t size)
-      : vmmo_cap_(vmmo_cap), paddr_(paddr), vaddr_(vaddr), size_(size) {}
+  OwnedMemoryRegion(uint64_t vmmo_cap, uint64_t vaddr, uint64_t size)
+      : vmmo_cap_(vmmo_cap), vaddr_(vaddr), size_(size) {}
   uint64_t vmmo_cap_ = 0;
-  uint64_t paddr_ = 0;
   uint64_t vaddr_ = 0;
   uint64_t size_ = 0;
 };
diff --git a/lib/mammoth/src/memory_region.cpp b/lib/mammoth/src/memory_region.cpp
index 9b7ea57..23e7db4 100644
--- a/lib/mammoth/src/memory_region.cpp
+++ b/lib/mammoth/src/memory_region.cpp
@@ -45,10 +45,8 @@ MappedMemoryRegion MappedMemoryRegion::FromCapability(z_cap_t vmmo_cap) {
 }
 
 OwnedMemoryRegion::OwnedMemoryRegion(OwnedMemoryRegion&& other)
-    : OwnedMemoryRegion(other.vmmo_cap_, other.paddr_, other.vaddr_,
-                        other.size_) {
+    : OwnedMemoryRegion(other.vmmo_cap_, other.vaddr_, other.size_) {
   other.vmmo_cap_ = 0;
-  other.paddr_ = 0;
   other.vaddr_ = 0;
   other.size_ = 0;
 }
@@ -58,11 +56,9 @@ OwnedMemoryRegion& OwnedMemoryRegion::operator=(OwnedMemoryRegion&& other) {
     check(ZCapRelease(vmmo_cap_));
   }
   vmmo_cap_ = other.vmmo_cap_;
-  paddr_ = other.paddr_;
   vaddr_ = other.vaddr_;
   size_ = other.size_;
   other.vmmo_cap_ = 0;
-  other.paddr_ = 0;
   other.vaddr_ = 0;
   other.size_ = 0;
   return *this;
@@ -70,6 +66,7 @@ OwnedMemoryRegion& OwnedMemoryRegion::operator=(OwnedMemoryRegion&& other) {
 
 OwnedMemoryRegion::~OwnedMemoryRegion() {
   if (vmmo_cap_ != 0) {
+    check(ZAddressSpaceUnmap(gSelfVmasCap, vaddr_, vaddr_ + size_));
     check(ZCapRelease(vmmo_cap_));
   }
 }
@@ -78,6 +75,8 @@ OwnedMemoryRegion OwnedMemoryRegion::FromCapability(z_cap_t vmmo_cap) {
   uint64_t vaddr;
   check(ZAddressSpaceMap(gSelfVmasCap, 0, vmmo_cap, &vaddr));
 
+  uint64_t size;
+  check(ZMemoryObjectInspect(vmmo_cap, &size));
   // FIXME: get the size here.
-  return OwnedMemoryRegion(vmmo_cap, 0, vaddr, 0);
+  return OwnedMemoryRegion(vmmo_cap, vaddr, size);
 }