-

diff --git a/modules/host/contractmanager/sector.go b/modules/host/contractmanager/sector.go
index f8ba8ba..cdfb532 100644
--- a/modules/host/contractmanager/sector.go
+++ b/modules/host/contractmanager/sector.go
@@ -63,17 +63,22 @@ type (
 	}
 )
 
-// readSector will read the sector in the file, starting from the provided
-// location.
-func readSector(f file, sectorIndex uint32) ([]byte, error) {
-	b := make([]byte, modules.SectorSize)
-	_, err := f.ReadAt(b, int64(uint64(sectorIndex)*modules.SectorSize))
+// readSectorPart will read the part of sector in the file.
+func readSectorPart(f file, sectorIndex, offset, length uint32) ([]byte, error) {
+	b := make([]byte, length)
+	_, err := f.ReadAt(b, int64(uint64(sectorIndex)*modules.SectorSize+uint64(offset)))
 	if err != nil {
 		return nil, build.ExtendErr("unable to read within storage folder", err)
 	}
 	return b, nil
 }
 
+// readSector will read the sector in the file, starting from the provided
+// location.
+func readSector(f file, sectorIndex uint32) ([]byte, error) {
+	return readSectorPart(f, sectorIndex, 0, uint32(modules.SectorSize))
+}
+
 // readFullMetadata will read a full sector metadata file into memory.
 func readFullMetadata(f file, numSectors int) ([]byte, error) {
 	sectorLookupBytes := make([]byte, numSectors*sectorMetadataDiskSize)
@@ -123,9 +128,8 @@ func (cm *ContractManager) managedSectorID(sectorRoot crypto.Hash) (id sectorID)
 	return id
 }
 
-// ReadSector will read a sector from the storage manager, returning the bytes
-// that match the input sector root.
-func (cm *ContractManager) ReadSector(root crypto.Hash) ([]byte, error) {
+// ReadSectorPart will read a part of a sector from the storage manager.
+func (cm *ContractManager) ReadSectorPart(root crypto.Hash, offset, length uint32) ([]byte, error) {
 	err := cm.tg.Add()
 	if err != nil {
 		return nil, err
@@ -153,7 +157,7 @@ func (cm *ContractManager) ReadSector(root crypto.Hash) ([]byte, error) {
 	}
 
 	// Read the sector.
-	sectorData, err := readSector(sf.sectorFile, sl.index)
+	sectorData, err := readSectorPart(sf.sectorFile, sl.index, offset, length)
 	if err != nil {
 		atomic.AddUint64(&sf.atomicFailedReads, 1)
 		return nil, build.ExtendErr("unable to fetch sector", err)
@@ -162,6 +166,12 @@ func (cm *ContractManager) ReadSector(root crypto.Hash) ([]byte, error) {
 	return sectorData, nil
 }
 
+// ReadSector will read a sector from the storage manager, returning the bytes
+// that match the input sector root.
+func (cm *ContractManager) ReadSector(root crypto.Hash) ([]byte, error) {
+	return cm.ReadSectorPart(root, 0, uint32(modules.SectorSize))
+}
+
 // managedLockSector grabs a sector lock.
 func (wal *writeAheadLog) managedLockSector(id sectorID) {
 	wal.mu.Lock()
diff --git a/modules/host/negotiatedownload.go b/modules/host/negotiatedownload.go
index c5c0e4e..3a1c6a6 100644
--- a/modules/host/negotiatedownload.go
+++ b/modules/host/negotiatedownload.go
@@ -89,11 +89,11 @@ func (h *Host) managedDownloadIteration(conn net.Conn, so *storageObligation) er
 
 		// Load the sectors and build the data payload.
 		for _, request := range requests {
-			sectorData, err := h.ReadSector(request.MerkleRoot)
+			sectorData, err := h.ReadSectorPart(request.MerkleRoot, uint32(request.Offset), uint32(request.Length))
 			if err != nil {
 				return extendErr("failed to load sector: ", ErrorInternal(err.Error()))
 			}
-			payload = append(payload, sectorData[request.Offset:request.Offset+request.Length])
+			payload = append(payload, sectorData)
 		}
 		return nil
 	}()
diff --git a/modules/storagemanager.go b/modules/storagemanager.go
index 6e3bf1f..d06bb5e 100644
--- a/modules/storagemanager.go
+++ b/modules/storagemanager.go
@@ -84,6 +84,9 @@ type (
 		// bytes that match the input sector root.
 		ReadSector(sectorRoot crypto.Hash) ([]byte, error)
 
+		// ReadSectorPart will read part of a sector from the storage manager.
+		ReadSectorPart(sectorRoot crypto.Hash, offset, length uint32) ([]byte, error)
+
 		// RemoveSector will remove a sector from the storage manager. The
 		// height at which the sector expires should be provided, so that the
 		// auto-expiry information for that sector can be properly updated.