diff --git a/prodos/directory.go b/prodos/directory.go
index 309ab6e..e00049c 100644
--- a/prodos/directory.go
+++ b/prodos/directory.go
@@ -73,7 +73,7 @@ func ReadDirectory(file *os.File, path string) (VolumeHeader, DirectoryHeader, [
 	return volumeHeader, directoryHeader, fileEntries
 }
 
-func GetFreeFileEntryInDirectory(file *os.File, directory string) (FileEntry, error) {
+func getFreeFileEntryInDirectory(file *os.File, directory string) (FileEntry, error) {
 	_, directoryHeader, _ := ReadDirectory(file, directory)
 	//DumpDirectoryHeader(directoryHeader)
 	blockNumber := directoryHeader.StartingBlock
diff --git a/prodos/file.go b/prodos/file.go
index b7171d3..37e148c 100644
--- a/prodos/file.go
+++ b/prodos/file.go
@@ -8,12 +8,15 @@ import (
 )
 
 func LoadFile(file *os.File, path string) ([]byte, error) {
-	fileEntry, err := GetFileEntry(file, path)
+	fileEntry, err := getFileEntry(file, path)
 	if err != nil {
 		return nil, err
 	}
 
-	blockList := getBlocklist(file, fileEntry)
+	blockList, err := getDataBlocklist(file, fileEntry)
+	if err != nil {
+		return nil, err
+	}
 
 	buffer := make([]byte, fileEntry.EndOfFile)
 
@@ -30,7 +33,7 @@ func LoadFile(file *os.File, path string) ([]byte, error) {
 func WriteFile(file *os.File, path string, fileType int, auxType int, buffer []byte) error {
 	directory, fileName := GetDirectoryAndFileNameFromPath(path)
 
-	existingFileEntry, _ := GetFileEntry(file, path)
+	existingFileEntry, _ := getFileEntry(file, path)
 	if existingFileEntry.StorageType != StorageDeleted {
 		DeleteFile(file, path)
 	}
@@ -38,50 +41,14 @@ func WriteFile(file *os.File, path string, fileType int, auxType int, buffer []b
 	// get list of blocks to write file to
 	blockList := createBlockList(file, len(buffer))
 
-	fileEntry, err := GetFreeFileEntryInDirectory(file, directory)
-	if err != nil {
-		return err
-	}
-
 	// seedling file
 	if len(buffer) <= 0x200 {
 		WriteBlock(file, blockList[0], buffer)
-		fileEntry.StorageType = StorageSeedling
 	}
 
 	// sapling file needs index block
 	if len(buffer) > 0x200 && len(buffer) <= 0x20000 {
-		fileEntry.StorageType = StorageSapling
-
-		// write index block with pointers to data blocks
-		indexBuffer := make([]byte, 512)
-		for i := 0; i < 256; i++ {
-			if i < len(blockList)-1 {
-				indexBuffer[i] = byte(blockList[i+1] & 0x00FF)
-				indexBuffer[i+256] = byte(blockList[i+1] >> 8)
-			}
-		}
-		WriteBlock(file, blockList[0], indexBuffer)
-
-		// write all data blocks
-		blockBuffer := make([]byte, 512)
-		blockPointer := 0
-		blockIndexNumber := 1
-		for i := 0; i < len(buffer); i++ {
-			blockBuffer[blockPointer] = buffer[i]
-			if blockPointer == 511 {
-				WriteBlock(file, blockList[blockIndexNumber], blockBuffer)
-				blockPointer = 0
-				blockIndexNumber++
-			} else if i == len(buffer)-1 {
-				for j := blockPointer; j < 512; j++ {
-					blockBuffer[j] = 0
-				}
-				WriteBlock(file, blockList[blockIndexNumber], blockBuffer)
-			} else {
-				blockPointer++
-			}
-		}
+		writeSaplingFile(file, buffer, blockList)
 	}
 
 	// TODO: add tree file
@@ -89,14 +56,13 @@ func WriteFile(file *os.File, path string, fileType int, auxType int, buffer []b
 		return errors.New("Files > 128KB not supported yet.")
 	}
 
-	// update volume bitmap
-	volumeBitmap := ReadVolumeBitmap(file)
-	for i := 0; i < len(blockList); i++ {
-		markBlockInVolumeBitmap(volumeBitmap, blockList[i])
-	}
-	writeVolumeBitmap(file, volumeBitmap)
+	updateVolumeBitmap(file, blockList)
 
 	// add file entry to directory
+	fileEntry, err := getFreeFileEntryInDirectory(file, directory)
+	if err != nil {
+		return err
+	}
 	fileEntry.FileName = fileName
 	fileEntry.BlocksUsed = len(blockList)
 	fileEntry.CreationTime = time.Now()
@@ -125,8 +91,48 @@ func WriteFile(file *os.File, path string, fileType int, auxType int, buffer []b
 	return nil
 }
 
+func updateVolumeBitmap(file *os.File, blockList []int) {
+	volumeBitmap := ReadVolumeBitmap(file)
+	for i := 0; i < len(blockList); i++ {
+		markBlockInVolumeBitmap(volumeBitmap, blockList[i])
+	}
+	writeVolumeBitmap(file, volumeBitmap)
+}
+
+func writeSaplingFile(file *os.File, buffer []byte, blockList []int) {
+	// write index block with pointers to data blocks
+	indexBuffer := make([]byte, 512)
+	for i := 0; i < 256; i++ {
+		if i < len(blockList)-1 {
+			indexBuffer[i] = byte(blockList[i+1] & 0x00FF)
+			indexBuffer[i+256] = byte(blockList[i+1] >> 8)
+		}
+	}
+	WriteBlock(file, blockList[0], indexBuffer)
+
+	// write all data blocks
+	blockBuffer := make([]byte, 512)
+	blockPointer := 0
+	blockIndexNumber := 1
+	for i := 0; i < len(buffer); i++ {
+		blockBuffer[blockPointer] = buffer[i]
+		if blockPointer == 511 {
+			WriteBlock(file, blockList[blockIndexNumber], blockBuffer)
+			blockPointer = 0
+			blockIndexNumber++
+		} else if i == len(buffer)-1 {
+			for j := blockPointer; j < 512; j++ {
+				blockBuffer[j] = 0
+			}
+			WriteBlock(file, blockList[blockIndexNumber], blockBuffer)
+		} else {
+			blockPointer++
+		}
+	}
+}
+
 func DeleteFile(file *os.File, path string) error {
-	fileEntry, err := GetFileEntry(file, path)
+	fileEntry, err := getFileEntry(file, path)
 	if err != nil {
 		return errors.New("File not found")
 	}
@@ -135,7 +141,10 @@ func DeleteFile(file *os.File, path string) error {
 	}
 
 	// free the blocks
-	blocks := getBlocklist(file, fileEntry)
+	blocks, err := getBlocklist(file, fileEntry)
+	if err != nil {
+		return err
+	}
 	volumeBitmap := ReadVolumeBitmap(file)
 	for i := 0; i < len(blocks); i++ {
 		freeBlockInVolumeBitmap(volumeBitmap, blocks[i])
@@ -157,30 +166,71 @@ func DeleteFile(file *os.File, path string) error {
 	return nil
 }
 
-func getBlocklist(file *os.File, fileEntry FileEntry) []int {
+func GetDirectoryAndFileNameFromPath(path string) (string, string) {
+	path = strings.ToUpper(path)
+	paths := strings.Split(path, "/")
+
+	var directoryBuilder strings.Builder
+
+	for i := 1; i < len(paths)-1; i++ {
+		directoryBuilder.WriteString("/")
+		directoryBuilder.WriteString(paths[i])
+	}
+
+	directory := directoryBuilder.String()
+	fileName := paths[len(paths)-1]
+
+	return directory, fileName
+}
+
+// Returns all blocks, including index blocks
+func getBlocklist(file *os.File, fileEntry FileEntry) ([]int, error) {
 	blocks := make([]int, fileEntry.BlocksUsed)
 
 	switch fileEntry.StorageType {
 	case StorageSeedling:
 		blocks[0] = fileEntry.KeyPointer
+		return blocks, nil
 	case StorageSapling:
 		index := ReadBlock(file, fileEntry.KeyPointer)
 		blocks[0] = fileEntry.KeyPointer
 		for i := 0; i < fileEntry.BlocksUsed-1; i++ {
 			blocks[i+1] = int(index[i]) + int(index[i+256])*256
 		}
+		return blocks, nil
 	case StorageTree:
 		masterIndex := ReadBlock(file, fileEntry.KeyPointer)
 		blocks[0] = fileEntry.KeyPointer
 		for i := 0; i < 128; i++ {
 			index := ReadBlock(file, int(masterIndex[i])+int(masterIndex[i+256])*256)
 			for j := 0; j < 256 && i*256+j < fileEntry.BlocksUsed; j++ {
+				if (int(index[j]) + int(index[j+256])*256) == 0 {
+					return blocks, nil
+				}
 				blocks[i*256+j] = int(index[j]) + int(index[j+256])*256
 			}
 		}
 	}
 
-	return blocks
+	return nil, errors.New("Unsupported file storage type")
+}
+
+func getDataBlocklist(file *os.File, fileEntry FileEntry) ([]int, error) {
+	switch fileEntry.StorageType {
+	case StorageSeedling:
+		blocks := make([]int, 1)
+		blocks[0] = fileEntry.KeyPointer
+		return blocks, nil
+	case StorageSapling:
+		blocks := make([]int, fileEntry.BlocksUsed-1)
+		index := ReadBlock(file, fileEntry.KeyPointer)
+		for i := 0; i < fileEntry.BlocksUsed-1; i++ {
+			blocks[i] = int(index[i]) + int(index[i+256])*256
+		}
+		return blocks, nil
+	}
+
+	return nil, errors.New("Unsupported file storage type")
 }
 
 func createBlockList(file *os.File, fileSize int) []int {
@@ -207,7 +257,7 @@ func createBlockList(file *os.File, fileSize int) []int {
 	return blockList
 }
 
-func GetFileEntry(file *os.File, path string) (FileEntry, error) {
+func getFileEntry(file *os.File, path string) (FileEntry, error) {
 	directory, fileName := GetDirectoryAndFileNameFromPath(path)
 	_, _, fileEntries := ReadDirectory(file, directory)
 
@@ -229,20 +279,3 @@ func GetFileEntry(file *os.File, path string) (FileEntry, error) {
 
 	return fileEntry, nil
 }
-
-func GetDirectoryAndFileNameFromPath(path string) (string, string) {
-	path = strings.ToUpper(path)
-	paths := strings.Split(path, "/")
-
-	var directoryBuilder strings.Builder
-
-	for i := 1; i < len(paths)-1; i++ {
-		directoryBuilder.WriteString("/")
-		directoryBuilder.WriteString(paths[i])
-	}
-
-	directory := directoryBuilder.String()
-	fileName := paths[len(paths)-1]
-
-	return directory, fileName
-}
diff --git a/prodos/format_test.go b/prodos/format_test.go
index f935d13..37e6fcb 100644
--- a/prodos/format_test.go
+++ b/prodos/format_test.go
@@ -21,7 +21,7 @@ func TestCreateVolume(t *testing.T) {
 		testname := fmt.Sprintf("%d", tt.blocks)
 		t.Run(testname, func(t *testing.T) {
 			fileName := os.TempDir() + "test-volume.hdv"
-			os.Remove(fileName)
+			defer os.Remove(fileName)
 			CreateVolume(fileName, tt.wantVolumeName, tt.blocks)
 
 			file, err := os.Open(fileName)