diff --git a/kernel/kernel/Memory/FileBackedRegion.cpp b/kernel/kernel/Memory/FileBackedRegion.cpp
index 0b66978b..42c54663 100644
--- a/kernel/kernel/Memory/FileBackedRegion.cpp
+++ b/kernel/kernel/Memory/FileBackedRegion.cpp
@@ -106,7 +106,7 @@ namespace Kernel
 		LockGuard _(m_shared_data->mutex);
 		for (vaddr_t page_addr = first_page; page_addr < last_page; page_addr += PAGE_SIZE)
 			if (contains(page_addr))
-				m_shared_data->sync((page_addr - m_vaddr) / PAGE_SIZE);
+				m_shared_data->sync((m_offset + page_addr - m_vaddr) / PAGE_SIZE);
 
 		return {};
 	}
@@ -135,17 +135,17 @@ namespace Kernel
 					return BAN::Error::from_errno(ENOMEM);
 
 				const size_t offset = (vaddr - m_vaddr) + m_offset;
-				ASSERT(offset % 4096 == 0);
+				ASSERT(offset % PAGE_SIZE == 0);
 
 				const size_t bytes = BAN::Math::min<size_t>(m_inode->size() - offset, PAGE_SIZE);
 
-				memset(m_shared_data->page_buffer, 0x00, PAGE_SIZE);
 				TRY(m_inode->read(offset, BAN::ByteSpan(m_shared_data->page_buffer, bytes)));
-				shared_data_has_correct_page = true;
+				memset(m_shared_data->page_buffer + bytes, 0, PAGE_SIZE - bytes);
 
 				PageTable::with_fast_page(m_shared_data->pages[shared_page_index], [&] {
 					memcpy(PageTable::fast_page_as_ptr(), m_shared_data->page_buffer, PAGE_SIZE);
 				});
+				shared_data_has_correct_page = true;
 			}
 
 			if (m_type == Type::PRIVATE && wants_write)
@@ -176,29 +176,17 @@ namespace Kernel
 		}
 		else
 		{
-			// page does not need remappings
-			if (m_type != Type::PRIVATE || !wants_write)
-				return false;
-			ASSERT(writable());
-
-			// page is already mapped as writable
-			if (m_page_table.get_page_flags(vaddr) & PageTable::Flags::ReadWrite)
-				return false;
+			ASSERT(m_type == Type::PRIVATE && wants_write);
 
 			const paddr_t paddr = Heap::get().take_free_page();
 			if (paddr == 0)
 				return BAN::Error::from_errno(ENOMEM);
 
-			ASSERT(m_shared_data);
-			LockGuard _(m_shared_data->mutex);
-			ASSERT(m_shared_data->pages[shared_page_index]);
+			ASSERT(&m_page_table == &PageTable::current());
+			PageTable::with_fast_page(paddr, [vaddr] {
+				memcpy(PageTable::fast_page_as_ptr(), reinterpret_cast<void*>(vaddr), PAGE_SIZE);
+			});
 
-			PageTable::with_fast_page(m_shared_data->pages[shared_page_index], [&] {
-				memcpy(m_shared_data->page_buffer, PageTable::fast_page_as_ptr(), PAGE_SIZE);
-			});
-			PageTable::with_fast_page(paddr, [&] {
-				memcpy(PageTable::fast_page_as_ptr(), m_shared_data->page_buffer, PAGE_SIZE);
-			});
 			m_dirty_pages[local_page_index] = paddr;
 			m_page_table.map_page_at(paddr, vaddr, m_flags);
 		}