diff --git a/lib/blockdev.h b/lib/blockdev.h
index 944bccf..ee422e8 100644
--- a/lib/blockdev.h
+++ b/lib/blockdev.h
@@ -50,5 +50,17 @@ typedef struct
 	 */
 	void (*rseek)(const int16_t offset);
 
+
+
+	/** Flush the data buffer if it's dirty.
+	 *
+	 * Should be called after each sequence of writes,
+	 * to avoid data loss.
+	 *
+	 * Tmplementations that do not need this should provide
+	 * a no-op function.
+	 */
+	void (*flush)(void);
+
 } BLOCKDEV;
 
diff --git a/lib/fat16.c b/lib/fat16.c
index 6ea4e44..0866529 100644
--- a/lib/fat16.c
+++ b/lib/fat16.c
@@ -24,7 +24,7 @@ uint16_t next_clu(const FAT16* fat, uint16_t cluster);
 uint32_t clu_offs(const FAT16* fat, uint16_t cluster, uint32_t addr);
 
 /** Read a file entry from directory (dir starting cluster, entry number) */
-void open_file(const FAT16* fat, FAT16_FILE* file, const uint16_t dir_cluster, const uint16_t num);
+void open_file(const FAT16* fat, FFILE* file, const uint16_t dir_cluster, const uint16_t num);
 
 /** Allocate and chain new cluster to a chain starting at given cluster */
 bool append_cluster(const FAT16* fat, const uint16_t clu);
@@ -42,7 +42,7 @@ bool free_cluster_chain(const FAT16* fat, uint16_t clu);
  * Check if there is already a file of given RAW name
  * Raw name - name as found on disk, not "display name".
  */
-bool dir_find_file_raw(FAT16_FILE* dir, const char* fname);
+bool dir_find_file_raw(FFILE* dir, const char* fname);
 
 /** Write a value into FAT */
 void write_fat(const FAT16* fat, const uint16_t cluster, const uint16_t value);
@@ -276,10 +276,10 @@ bool free_cluster_chain(const FAT16* fat, uint16_t clu)
  * Check if there is already a file of given RAW name
  * Raw name - name as found on disk, not "display name".
  */
-bool dir_find_file_raw(FAT16_FILE* dir, const char* fname)
+bool dir_find_file_raw(FFILE* dir, const char* fname)
 {
 	// rewind
-	fat16_first(dir);
+	ff_first(dir);
 
 	do
 	{
@@ -299,7 +299,7 @@ bool dir_find_file_raw(FAT16_FILE* dir, const char* fname)
 			return true; // file is already open.
 		}
 	}
-	while (fat16_next(dir));
+	while (ff_next(dir));
 
 	return false;
 }
@@ -311,7 +311,7 @@ bool dir_find_file_raw(FAT16_FILE* dir, const char* fname)
  * dir_cluster ... directory start cluster
  * num ... entry number in the directory
  */
-void open_file(const FAT16* fat, FAT16_FILE* file, const uint16_t dir_cluster, const uint16_t num)
+void open_file(const FAT16* fat, FFILE* file, const uint16_t dir_cluster, const uint16_t num)
 {
 	// Resolve starting address
 	uint32_t addr;
@@ -397,7 +397,7 @@ void open_file(const FAT16* fat, FAT16_FILE* file, const uint16_t dir_cluster, c
 	}
 
 	// Init cursors
-	fat16_seek(file, 0);
+	ff_seek(file, 0);
 }
 
 
@@ -406,7 +406,7 @@ void open_file(const FAT16* fat, FAT16_FILE* file, const uint16_t dir_cluster, c
  * Write information into a file header.
  * "file" is an open handle.
  */
-void write_file_header(FAT16_FILE* file, const char* fname_raw, const uint8_t attribs, const uint16_t clu_start)
+void write_file_header(FFILE* file, const char* fname_raw, const uint8_t attribs, const uint16_t clu_start)
 {
 	const BLOCKDEV* dev = file->fat->dev;
 
@@ -442,7 +442,7 @@ void write_file_header(FAT16_FILE* file, const char* fname_raw, const uint8_t at
 // =============== PUBLIC FUNCTION IMPLEMENTATIONS =================
 
 /** Initialize a FAT16 handle */
-bool fat16_init(const BLOCKDEV* dev, FAT16* fat)
+bool ff_init(const BLOCKDEV* dev, FAT16* fat)
 {
 	const uint32_t bs_a = find_bs(dev);
 
@@ -464,7 +464,7 @@ bool fat16_init(const BLOCKDEV* dev, FAT16* fat)
  * Move file cursor to a position relative to file start
  * Allows seek past end of file, will allocate new cluster if needed.
  */
-bool fat16_seek(FAT16_FILE* file, uint32_t addr)
+bool ff_seek(FFILE* file, uint32_t addr)
 {
 	const FAT16* fat = file->fat;
 
@@ -512,7 +512,7 @@ bool fat16_seek(FAT16_FILE* file, uint32_t addr)
  * Check if file is a regular file or directory entry.
  * Those files can be shown to user.
  */
-bool fat16_is_regular(const FAT16_FILE* file)
+bool ff_is_regular(const FFILE* file)
 {
 	switch (file->type)
 	{
@@ -530,7 +530,7 @@ bool fat16_is_regular(const FAT16_FILE* file)
 
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
 
-uint16_t fat16_read(FAT16_FILE* file, void* target, uint16_t len)
+uint16_t ff_read(FFILE* file, void* target, uint16_t len)
 {
 	if (file->cur_abs == 0xFFFF)
 		return 0; // file at the end already
@@ -580,14 +580,23 @@ uint16_t fat16_read(FAT16_FILE* file, void* target, uint16_t len)
 }
 
 
-bool fat16_write(FAT16_FILE* file, void* source, uint32_t len)
+bool ff_write_str(FFILE* file, const char* source)
+{
+	uint16_t len = 0;
+	for (; source[len] != 0; len++);
+
+	return ff_write(file, source, len);
+}
+
+
+bool ff_write(FFILE* file, const void* source, uint32_t len)
 {
 	const FAT16* fat = file->fat;
 	const BLOCKDEV* dev = fat->dev;
 
 
 	if (file->cur_abs == 0xFFFF)
-		return false; // file at the end already
+		return false; // file past it's end (rare)
 
 	// Attempt to write past end of file
 	if (file->cur_rel + len >= file->size)
@@ -596,14 +605,14 @@ bool fat16_write(FAT16_FILE* file, void* source, uint32_t len)
 
 		// Seek to the last position
 		// -> fseek will allocate clusters
-		if (!fat16_seek(file, pos_start + len))
+		if (!ff_seek(file, pos_start + len))
 			return false; // error in seek
 
 		// Write starts beyond EOF - creating a zero-filled "hole"
-		if (file->cur_rel > file->size)
+		if (pos_start > file->size + 1)
 		{
 			// Seek to the end of valid data
-			fat16_seek(file, file->size);
+			ff_seek(file, file->size);
 
 			// fill space between EOF and start-of-write with zeros
 			uint32_t fill = pos_start - file->size;
@@ -631,31 +640,44 @@ bool fat16_write(FAT16_FILE* file, void* source, uint32_t len)
 			}
 		}
 
-		// Save new size
-		fat16_resize(file, pos_start + len);
+		// Store new size
+		file->size = pos_start + len;
 
 		// Seek back to where it was before
-		fat16_seek(file, pos_start);
+		ff_seek(file, pos_start);
 	} // (end zerofill)
 
 
 	// write the data
 	while (len > 0)
 	{
-		// How much can be stored in this cluster
-		const uint16_t chunk = MIN(fat->bs.bytes_per_cluster - file->cur_ofs, len);
-
-		// store the chunk
 		dev->seek(file->cur_abs);
-		dev->store(source, chunk);
+		uint16_t chunk;
 
-		// advance cursors
-		file->cur_abs += chunk;
-		file->cur_rel += chunk;
-		file->cur_ofs += chunk;
+		if (len == 1)
+		{
+			dev->write(*((uint8_t*)source));
+			file->cur_abs++;
+			file->cur_rel++;
+			file->cur_ofs++;
+			chunk = 1;
 
-		// Pointer arith!
-		source += chunk; // advance the source pointer
+		}
+		else
+		{
+			// How much can be stored in this cluster
+			chunk = MIN(fat->bs.bytes_per_cluster - file->cur_ofs, len);
+
+			dev->store(source, chunk);
+
+			// advance cursors
+			file->cur_abs += chunk;
+			file->cur_rel += chunk;
+			file->cur_ofs += chunk;
+
+			// Pointer arith!
+			source += chunk; // advance the source pointer
+		}
 
 		// detect cluster overflow
 		if (file->cur_ofs >= fat->bs.bytes_per_cluster)
@@ -676,7 +698,7 @@ bool fat16_write(FAT16_FILE* file, void* source, uint32_t len)
 
 
 /** Open next file in the directory */
-bool fat16_next(FAT16_FILE* file)
+bool ff_next(FFILE* file)
 {
 	const FAT16* fat = file->fat;
 	const BLOCKDEV* dev = fat->dev;
@@ -700,7 +722,7 @@ bool fat16_next(FAT16_FILE* file)
 
 
 /** Open previous file in the directory */
-bool fat16_prev(FAT16_FILE* file)
+bool ff_prev(FFILE* file)
 {
 	if (file->num == 0)
 		return false; // first file already
@@ -712,14 +734,14 @@ bool fat16_prev(FAT16_FILE* file)
 
 
 /** Rewind to first file in directory */
-void fat16_first(FAT16_FILE* file)
+void ff_first(FFILE* file)
 {
 	open_file(file->fat, file, file->clu, 0);
 }
 
 
 /** Open a directory denoted by the file. */
-bool fat16_opendir(FAT16_FILE* dir)
+bool ff_opendir(FFILE* dir)
 {
 	// Don't open non-dirs and "." directory.
 	if (!(dir->attribs & FA_DIR) || dir->type == FT_SELF)
@@ -730,7 +752,7 @@ bool fat16_opendir(FAT16_FILE* dir)
 }
 
 
-void fat16_root(const FAT16* fat, FAT16_FILE* file)
+void ff_root(const FAT16* fat, FFILE* file)
 {
 	open_file(fat, file, 0, 0);
 }
@@ -741,16 +763,16 @@ void fat16_root(const FAT16* fat, FAT16_FILE* file)
  * If file is found, "dir" will contain it's handle.
  * Either way, "dir" gets modified and you may need to rewind it afterwards.
  */
-bool fat16_find(FAT16_FILE* dir, const char* name)
+bool ff_open(FFILE* dir, const char* name)
 {
 	char fname[11];
-	fat16_rawname(name, fname);
+	ff_rawname(name, fname);
 	return dir_find_file_raw(dir, fname);
 }
 
 
 /** Go through a directory, and "open" first FT_NONE or FT_DELETED file entry. */
-bool find_empty_file_slot(FAT16_FILE* file)
+bool find_empty_file_slot(FFILE* file)
 {
 	const uint16_t clu = file->clu;
 	const FAT16* fat = file->fat;
@@ -795,15 +817,15 @@ bool find_empty_file_slot(FAT16_FILE* file)
 
 
 
-bool fat16_mkfile(FAT16_FILE* file, const char* name)
+bool ff_newfile(FFILE* file, const char* name)
 {
 	// Convert filename to zero padded raw string
 	char fname[11];
-	fat16_rawname(name, fname);
+	ff_rawname(name, fname);
 
 	// Abort if file already exists
 	bool exists = dir_find_file_raw(file, fname);
-	fat16_first(file); // rewind dir
+	ff_first(file); // rewind dir
 	if (exists)
 		return false; // file already exists in the dir.
 
@@ -823,15 +845,15 @@ bool fat16_mkfile(FAT16_FILE* file, const char* name)
  * Create a sub-directory of given name.
  * Directory is allocated and populated with entries "." and ".."
  */
-bool fat16_mkdir(FAT16_FILE* file, const char* name)
+bool ff_mkdir(FFILE* file, const char* name)
 {
 	// Convert filename to zero padded raw string
 	char fname[11];
-	fat16_rawname(name, fname);
+	ff_rawname(name, fname);
 
 	// Abort if file already exists
 	bool exists = dir_find_file_raw(file, fname);
-	fat16_first(file); // rewind dir
+	ff_first(file); // rewind dir
 	if (exists)
 		return false; // file already exusts in the dir.
 
@@ -854,20 +876,20 @@ bool fat16_mkdir(FAT16_FILE* file, const char* name)
 	write_file_header(file, "..         ", FA_DIR, parent_clu);
 
 	// rewind.
-	fat16_first(file);
+	ff_first(file);
 
 	return true;
 }
 
 
-char* fat16_disk_label(const FAT16* fat, char* label_out)
+char* ff_disk_label(const FAT16* fat, char* label_out)
 {
-	FAT16_FILE first;
-	fat16_root(fat, &first);
+	FFILE first;
+	ff_root(fat, &first);
 
 	if (first.type == FT_LABEL)
 	{
-		return fat16_dispname(&first, label_out);
+		return ff_dispname(&first, label_out);
 	}
 
 	// find where spaces end
@@ -890,7 +912,7 @@ char* fat16_disk_label(const FAT16* fat, char* label_out)
 }
 
 
-char* fat16_dispname(const FAT16_FILE* file, char* disp_out)
+char* ff_dispname(const FFILE* file, char* disp_out)
 {
 	// Cannot get name for special files
 	if (file->type == FT_NONE ||        // not-yet-used directory location
@@ -940,7 +962,7 @@ char* fat16_dispname(const FAT16_FILE* file, char* disp_out)
 }
 
 
-char* fat16_rawname(const char* disp_in, char* raw_out)
+char* ff_rawname(const char* disp_in, char* raw_out)
 {
 	uint8_t name_c = 0, wr_c = 0;
 	bool filling = false;
@@ -1014,7 +1036,7 @@ char* fat16_rawname(const char* disp_in, char* raw_out)
 }
 
 
-FSAVEPOS fat16_savepos(const FAT16_FILE* file)
+FSAVEPOS ff_savepos(const FFILE* file)
 {
 	FSAVEPOS fsp;
 	fsp.clu = file->clu;
@@ -1024,28 +1046,31 @@ FSAVEPOS fat16_savepos(const FAT16_FILE* file)
 }
 
 
-void fat16_reopen(FAT16_FILE* file, const FSAVEPOS* pos)
+void ff_reopen(FFILE* file, const FSAVEPOS* pos)
 {
 	open_file(file->fat, file, pos->clu, pos->num);
-	fat16_seek(file, pos->cur_rel);
+	ff_seek(file, pos->cur_rel);
 }
 
 
-/** Write new file size (also to the disk). Does not allocate clusters. */
-void fat16_resize(FAT16_FILE* file, uint32_t size)
+void ff_flush_file(FFILE* file)
 {
 	const FAT16* fat = file->fat;
 	const BLOCKDEV* dev = file->fat->dev;
 
+	// Store open page
+	dev->flush();
+
+	// Store file size
+
 	// Find address for storing the size
 	const uint32_t addr = clu_offs(fat, file->clu, file->num * 32 + 28);
-	file->size = size;
 
 	dev->seek(addr);
-	dev->store(&size, 4);
+	dev->store(&(file->size), 4);
 
 	// Seek to the end of the file, to make sure clusters are allocated
-	fat16_seek(file, size - 1);
+	ff_seek(file, file->size - 1);
 
 	const uint16_t next = next_clu(fat, file->cur_clu);
 	if (next != 0xFFFF)
@@ -1057,8 +1082,10 @@ void fat16_resize(FAT16_FILE* file, uint32_t size)
 	}
 }
 
+
+
 /** Low level no-check file delete and free */
-void delete_file_do(FAT16_FILE* file)
+void delete_file_do(FFILE* file)
 {
 	const FAT16* fat = file->fat;
 
@@ -1080,7 +1107,7 @@ void delete_file_do(FAT16_FILE* file)
 
 
 /** Delete a simple file */
-bool fat16_rmfile(FAT16_FILE* file)
+bool ff_rmfile(FFILE* file)
 {
 	switch (file->type)
 	{
@@ -1099,15 +1126,15 @@ bool fat16_rmfile(FAT16_FILE* file)
 
 
 /** Delete an empty directory */
-bool fat16_rmdir(FAT16_FILE* file)
+bool ff_rmdir(FFILE* file)
 {
 	if (file->type != FT_SUBDIR)
 		return false; // not a subdirectory entry
 
-	const FSAVEPOS orig = fat16_savepos(file);
+	const FSAVEPOS orig = ff_savepos(file);
 
 	// Open the subdir
-	if (!fat16_opendir(file))
+	if (!ff_opendir(file))
 		return false; // could not open
 
 	// Look for valid files and subdirs in the directory
@@ -1124,16 +1151,16 @@ bool fat16_rmdir(FAT16_FILE* file)
 		{
 			// Valid child file was found, aborting.
 			// reopen original file
-			fat16_reopen(file, &orig);
+			ff_reopen(file, &orig);
 			return false;
 		}
 
 		if (cnt < 2) cnt++;
 	}
-	while (fat16_next(file));
+	while (ff_next(file));
 
 	// reopen original file
-	fat16_reopen(file, &orig);
+	ff_reopen(file, &orig);
 
 	// and delete as ordinary file
 	delete_file_do(file);
@@ -1142,7 +1169,7 @@ bool fat16_rmdir(FAT16_FILE* file)
 }
 
 
-bool fat16_delete(FAT16_FILE* file)
+bool ff_delete(FFILE* file)
 {
 	switch (file->type)
 	{
@@ -1153,7 +1180,7 @@ bool fat16_delete(FAT16_FILE* file)
 		case FT_SUBDIR:; // semicolon needed to allow declaration after "case"
 
 			// store original file location
-			const FSAVEPOS orig = fat16_savepos(file);
+			const FSAVEPOS orig = ff_savepos(file);
 
 			// open the directory (skip "." and "..")
 			open_file(file->fat, file, file->clu_start, 2);
@@ -1161,32 +1188,32 @@ bool fat16_delete(FAT16_FILE* file)
 			// delete all children
 			do
 			{
-				if (!fat16_delete(file))
+				if (!ff_delete(file))
 				{
 					// failure
 					// reopen original file
-					fat16_reopen(file, &orig);
+					ff_reopen(file, &orig);
 					return false;
 				}
 			}
-			while (fat16_next(file));
+			while (ff_next(file));
 
 			// go up and delete the dir
-			fat16_reopen(file, &orig);
-			return fat16_rmdir(file);
+			ff_reopen(file, &orig);
+			return ff_rmdir(file);
 
 		default:
 			// try to delete as a regular file
-			return fat16_rmfile(file);
+			return ff_rmfile(file);
 	}
 }
 
 
-bool fat16_parent(FAT16_FILE* file)
+bool ff_parent(FFILE* file)
 {
 	// open second entry of the directory
 	open_file(file->fat, file, file->clu, 1);
-	const FSAVEPOS orig = fat16_savepos(file);
+	const FSAVEPOS orig = ff_savepos(file);
 
 	// if it's a valid PARENT link, follow it.
 	if (file->type == FT_PARENT)
@@ -1198,7 +1225,7 @@ bool fat16_parent(FAT16_FILE* file)
 	{
 		// in root already?
 		// reopen original file
-		fat16_reopen(file, &orig);
+		ff_reopen(file, &orig);
 		return false;
 	}
 }
diff --git a/lib/fat16.h b/lib/fat16.h
index c0cdee7..149daec 100644
--- a/lib/fat16.h
+++ b/lib/fat16.h
@@ -99,24 +99,31 @@ typedef struct __attribute__((packed))
 	// Pointer to the FAT16 handle. (internal)
 	const FAT16* fat;
 }
-FAT16_FILE;
+FFILE;
+
+
+/**
+ * Store modified file metadata and flush it to disk.
+ */
+void ff_flush_file(FFILE* file);
+
 
 /**
  * Save a file "position" into a struct, for later restoration.
  * Cursor is also saved.
  */
-FSAVEPOS fat16_savepos(const FAT16_FILE* file);
+FSAVEPOS ff_savepos(const FFILE* file);
 
 /**
  * Restore a file from a saved position.
  */
-void fat16_reopen(FAT16_FILE* file, const FSAVEPOS* pos);
+void ff_reopen(FFILE* file, const FSAVEPOS* pos);
 
 
 /**
  * Initialize the file system - store into "fat"
  */
-bool fat16_init(const BLOCKDEV* dev, FAT16* fat);
+bool ff_init(const BLOCKDEV* dev, FAT16* fat);
 
 
 /**
@@ -124,7 +131,7 @@ bool fat16_init(const BLOCKDEV* dev, FAT16* fat);
  * The file may be invalid (eg. a volume label, deleted etc),
  * or blank (type FT_NONE) if the filesystem is empty.
  */
-void fat16_root(const FAT16* fat, FAT16_FILE* file);
+void ff_root(const FAT16* fat, FFILE* file);
 
 
 /**
@@ -134,7 +141,7 @@ void fat16_root(const FAT16* fat, FAT16_FILE* file);
  * @param fat       the FAT handle
  * @param label_out string to store the label in. Should have at least 12 bytes.
  */
-char* fat16_disk_label(const FAT16* fat, char* label_out);
+char* ff_disk_label(const FAT16* fat, char* label_out);
 
 
 // ----------- FILE I/O -------------
@@ -144,21 +151,26 @@ char* fat16_disk_label(const FAT16* fat, char* label_out);
  * Move file cursor to a position relative to file start
  * Returns false on I/O error (bad file, out of range...)
  */
-bool fat16_seek(FAT16_FILE* file, uint32_t addr);
+bool ff_seek(FFILE* file, uint32_t addr);
 
 
 /**
  * Read bytes from file into memory
  * Returns number of bytes read, 0 on error.
  */
-uint16_t fat16_read(FAT16_FILE* file, void* target, uint16_t len);
+uint16_t ff_read(FFILE* file, void* target, uint16_t len);
 
 
 /**
  * Write into file at a "seek" position.
- * "seek" cursor must be within (0..filesize)
  */
-bool fat16_write(FAT16_FILE* file, void* source, uint32_t len);
+bool ff_write(FFILE* file, const void* source, uint32_t len);
+
+
+/**
+ * Store a 0-terminated string at cursor.
+ */
+bool ff_write_str(FFILE* file, const char* source);
 
 
 /**
@@ -167,14 +179,14 @@ bool fat16_write(FAT16_FILE* file, void* source, uint32_t len);
  * file ... open directory; new file is opened into this handle.
  * name ... name of the new file, including extension
  */
-bool fat16_mkfile(FAT16_FILE* file, const char* name);
+bool ff_newfile(FFILE* file, const char* name);
 
 
 /**
  * Create a sub-directory of given name.
  * Directory is allocated and populated with entries "." and ".."
  */
-bool fat16_mkdir(FAT16_FILE* file, const char* name);
+bool ff_mkdir(FFILE* file, const char* name);
 
 
 /**
@@ -183,26 +195,26 @@ bool fat16_mkdir(FAT16_FILE* file, const char* name);
  *
  * Useful mainly for shrinking.
  */
-void fat16_resize(FAT16_FILE* file, uint32_t size);
+void set_file_size(FFILE* file, uint32_t size);
 
 
 /**
  * Delete a *FILE* and free it's clusters.
  */
-bool fat16_rmfile(FAT16_FILE* file);
+bool ff_rmfile(FFILE* file);
 
 
 /**
  * Delete an empty *DIRECTORY* and free it's clusters.
  */
-bool fat16_rmdir(FAT16_FILE* file);
+bool ff_rmdir(FFILE* file);
 
 
 /**
  * Delete a file or directory, even FT_LFN and FT_INVALID.
  * Directories are deleted recursively (!)
  */
-bool fat16_delete(FAT16_FILE* file);
+bool ff_delete(FFILE* file);
 
 
 
@@ -210,55 +222,55 @@ bool fat16_delete(FAT16_FILE* file);
 
 
 /** Go to previous file in the directory (false = no prev file) */
-bool fat16_prev(FAT16_FILE* file);
+bool ff_prev(FFILE* file);
 
 
 /** Go to next file in directory (false = no next file) */
-bool fat16_next(FAT16_FILE* file);
+bool ff_next(FFILE* file);
 
 
 /**
  * Open a subdirectory denoted by the file.
  * Provided handle changes to the first entry of the directory.
  */
-bool fat16_opendir(FAT16_FILE* dir);
+bool ff_opendir(FFILE* dir);
 
 
 /**
  * Open a parent directory. Fails in root.
  * Provided handle changes to the first entry of the parent directory.
  */
-bool fat16_parent(FAT16_FILE* file);
+bool ff_parent(FFILE* file);
 
 
 /** Jump to first file in this directory */
-void fat16_first(FAT16_FILE* file);
+void ff_first(FFILE* file);
 
 
 /**
- * Find a file with given "display name" in this directory.
+ * Find a file with given "display name" in this directory, and open it.
  * If file is found, "dir" will contain it's handle.
  * If file is NOT found, the handle points to the last entry of the directory.
  */
-bool fat16_find(FAT16_FILE* dir, const char* name);
+bool ff_open(FFILE* dir, const char* name);
 
 
 // -------- FILE INSPECTION -----------
 
 /** Check if file is a valid entry, or long-name/label/deleted */
-bool fat16_is_regular(const FAT16_FILE* file);
+bool ff_is_regular(const FFILE* file);
 
 
 /**
  * Resolve a file name, trim spaces and add null terminator.
  * Returns the passed char*, or NULL on error.
  */
-char* fat16_dispname(const FAT16_FILE* file, char* disp_out);
+char* ff_dispname(const FFILE* file, char* disp_out);
 
 
 /**
  * Convert filename to zero-padded fixed length one
  * Returns the passed char*.
  */
-char* fat16_rawname(const char* disp_in, char* raw_out);
+char* ff_rawname(const char* disp_in, char* raw_out);
 
diff --git a/lib/sd.h b/lib/sd.h
index 73fb8db..c57fc51 100644
--- a/lib/sd.h
+++ b/lib/sd.h
@@ -15,8 +15,6 @@
 
 #include "iopins.h"
 #include "spi.h"
-#include "uart.h"
-#include "stream.h"
 
 /** Init SD card on SPI */
 bool sd_init();
diff --git a/lib/sd_blockdev.c b/lib/sd_blockdev.c
index 574f7dd..f363f47 100644
--- a/lib/sd_blockdev.c
+++ b/lib/sd_blockdev.c
@@ -16,6 +16,7 @@ uint8_t dev_read();
 void dev_write(const uint8_t b);
 void dev_seek(const uint32_t addr);
 void dev_rseek(const int16_t offset);
+void dev_flush();
 
 
 /** Sector buffer */
@@ -36,7 +37,7 @@ uint16_t cursor_offs;
 
 
 /** Flush the buffer, if it's dirty */
-void sdb_flush()
+void dev_flush()
 {
 	if (buff_dirty)
 	{
@@ -49,11 +50,12 @@ void sdb_flush()
 void load_sector(const uint32_t addr)
 {
 	// do not load if already loaded
-	if (buff_valid && buff_addr == addr) {
+	if (buff_valid && buff_addr == addr)
+	{
 		return;
 	}
 
-	sdb_flush();
+	dev_flush();
 
 	// read entire sector
 	sd_read(addr, 0, buff, 0, 512);
@@ -90,8 +92,17 @@ inline void handle_cursor_ov()
 void dev_write(const uint8_t b)
 {
 	load_sector(cursor_sec);
-	buff[cursor_offs++] = b;
-	buff_dirty = true;
+
+	// dirty only if changed
+	if (buff[cursor_offs] != b)
+	{
+		buff[cursor_offs++] = b;
+		buff_dirty = true;
+	}
+	else
+	{
+		cursor_offs++;
+	}
 
 	handle_cursor_ov();
 }
@@ -158,7 +169,7 @@ void dev_rseek(const int16_t offset)
 /** Init SD card block device */
 bool sdb_init(BLOCKDEV* dev)
 {
-	if(!sd_init()) return false;
+	if (!sd_init()) return false;
 
 	dev->load = &dev_load;
 	dev->store = &dev_store;
@@ -166,6 +177,7 @@ bool sdb_init(BLOCKDEV* dev)
 	dev->write = &dev_write;
 	dev->seek = &dev_seek;
 	dev->rseek = &dev_rseek;
+	dev->flush = &dev_flush;
 
 	return true;
 }
diff --git a/lib/sd_blockdev.h b/lib/sd_blockdev.h
index 66fce6c..68e53b8 100644
--- a/lib/sd_blockdev.h
+++ b/lib/sd_blockdev.h
@@ -2,13 +2,5 @@
 
 #include "blockdev.h"
 
-/**
- * Flush the sector buffer if it's dirty.
- *
- * Should be called after each sequence of writes,
- * to avoid data loss.
- */
-void sdb_flush();
-
 /** Initialize the SD card block device */
 bool sdb_init(BLOCKDEV* dev);
diff --git a/lib/sd_fat.c b/lib/sd_fat.c
index 85117bb..519034d 100644
--- a/lib/sd_fat.c
+++ b/lib/sd_fat.c
@@ -8,27 +8,60 @@
 FAT16 _fat;
 BLOCKDEV _dev;
 
+
+static STREAM _s;
+STREAM* sdf_stream = &_s;
+
+FFILE* stream_file;
+bool stream_active = false;
+
+void stream_tx(uint8_t b)
+{
+	if (!stream_active) return;
+	ff_write(stream_file, &b, 1);
+}
+
+
+uint8_t stream_rx()
+{
+	if (!stream_active) return 0;
+
+	uint8_t b;
+	ff_read(stream_file, &b, 1);
+	return b;
+}
+
+void sdf_open_stream(FFILE* file)
+{
+	stream_active = true;
+	stream_file = file;
+}
+
+
 bool sdfat_inited = false;
 
-bool sdfat_init()
+bool sdf_init()
 {
 	if (sdfat_inited) return true;
 	sdfat_inited = true;
 
 	if (!sdb_init(&_dev)) return false;
-	if (!fat16_init(&_dev, &_fat)) return false;
+	if (!ff_init(&_dev, &_fat)) return false;
+
+	sdf_stream->rx = &stream_rx;
+	sdf_stream->tx = &stream_tx;
 
 	return true;
 }
 
 
-void sdfat_root(FAT16_FILE* file)
+void sdf_root(FFILE* file)
 {
-	fat16_root(&_fat, file);
+	ff_root(&_fat, file);
 }
 
 
-void sdfat_disk_label(char* str)
+void sdf_disk_label(char* str)
 {
-	fat16_disk_label(&_fat, str);
+	ff_disk_label(&_fat, str);
 }
diff --git a/lib/sd_fat.h b/lib/sd_fat.h
index 2cf835b..1940ca0 100644
--- a/lib/sd_fat.h
+++ b/lib/sd_fat.h
@@ -1,19 +1,30 @@
 #pragma once
 
 //
-// FAT-on-SD helpers
+// FAT-on-SD helpers.
+//
+// This can be used for convenience, as it does all the init for you
+// and hides the implementation. All regular ff_* functions will work on the FFILE.
 //
 
 #include "fat16.h"
+#include "stream.h"
 
 /** Initialize FAT16 filesystem on a SPI-connected SD card */
-bool sdfat_init();
+bool sdf_init();
 
 /** Get first file of the root folder. */
-void sdfat_root(FAT16_FILE* file);
+void sdf_root(FFILE* file);
 
 /** Get a disk label. Str should have 12 chars. */
-void sdfat_disk_label(char* str);
+void sdf_disk_label(char* str);
+
+extern STREAM* sdf_stream;
 
-/** Flush the SD buffer (alis of sdb_flush()) */
-#define sdfat_flush() sdb_flush()
+/**
+ * Open a stream for a file. There can be only one stream at a time.
+ *
+ * The stream will operate at the current file's cursor, just like
+ * ff_read and ff_write.
+*/
+void sdf_open_stream(FFILE* file);
diff --git a/lib/stream.c b/lib/stream.c
index ae7567b..fdf4bcb 100644
--- a/lib/stream.c
+++ b/lib/stream.c
@@ -18,7 +18,7 @@ void put_bytes(const STREAM *p, const uint8_t* str, const uint16_t len)
 }
 
 
-void put_str(const STREAM *p, char* str)
+void put_str(const STREAM *p, const char *str)
 {
 	char c;
 	while ((c = *str++))
@@ -41,6 +41,11 @@ void put_str_P(const STREAM *p, const char* str)
 static void _putnf(const STREAM *p, const uint8_t places);
 
 
+void put_c(const STREAM *p, const uint8_t c)
+{
+	p->tx(c);
+}
+
 /** Send signed int8 */
 void put_u8(const STREAM *p, const uint8_t num)
 {
diff --git a/lib/stream.h b/lib/stream.h
index 9d7ff0f..96f13a8 100644
--- a/lib/stream.h
+++ b/lib/stream.h
@@ -31,74 +31,75 @@ typedef struct
 
 
 /** Send bytes to stream */
-void put_bytes(const STREAM *p, const uint8_t* str, const uint16_t len);
+void put_bytes(const STREAM *p, const uint8_t* str, uint16_t len);
 
 
 /** Print string into a stream */
-void put_str(const STREAM *p, char* str);
+void put_str(const STREAM *p, const char *str);
 
 
 /** Print a programspace string into a stream */
 void put_str_P(const STREAM *p, const char* str);
 
+/** Put a char/byte. Basically the same as p->tx() */
+void put_c(const STREAM *p, uint8_t c);
 
 /** Send signed int8 */
-#define put_char(p, c) (p)->tx((c))
-void put_u8(const STREAM *p, const uint8_t num);
+void put_u8(const STREAM *p, uint8_t num);
 
 
 /** Send unsigned int8 */
-void put_i8(const STREAM *p, const int8_t num);
+void put_i8(const STREAM *p, int8_t num);
 
 
 /** Send unsigned int */
-void put_u16(const STREAM *p, const uint16_t num);
+void put_u16(const STREAM *p, uint16_t num);
 
 
 /** Send signed int */
-void put_i16(const STREAM *p, const int16_t num);
+void put_i16(const STREAM *p, int16_t num);
 
 
 /** Send unsigned long */
-void put_u32(const STREAM *p, const uint32_t num);
+void put_u32(const STREAM *p, uint32_t num);
 
 
 /** Send signed long */
-void put_i32(const STREAM *p, const int32_t num);
+void put_i32(const STREAM *p, int32_t num);
 
 
 /** Send unsigned int8 */
-void put_x8(const STREAM *p, const uint8_t num);
+void put_x8(const STREAM *p, uint8_t num);
 
 
 /** Send int as hex */
-void put_x16(const STREAM *p, const uint16_t num);
+void put_x16(const STREAM *p, uint16_t num);
 
 
 /** Send long as hex */
-void put_x32(const STREAM *p, const uint32_t num);
+void put_x32(const STREAM *p, uint32_t num);
 
 
 /** Send long long as hex */
-void put_x64(const STREAM *p, const uint64_t num);
+void put_x64(const STREAM *p, uint64_t num);
 
 
 // float variant doesn't make sense for 8-bit int
 
 /** Send unsigned int as float */
-void put_u16f(const STREAM *p, const uint16_t num, const uint8_t places);
+void put_u16f(const STREAM *p, uint16_t num, uint8_t places);
 
 
 /** Send signed int as float */
-void put_i16f(const STREAM *p, const int16_t num, const uint8_t places);
+void put_i16f(const STREAM *p, int16_t num, uint8_t places);
 
 
 /** Send unsigned long as float */
-void put_u32f(const STREAM *p, const uint32_t num, const uint8_t places);
+void put_u32f(const STREAM *p, uint32_t num, uint8_t places);
 
 
 /** Send signed long as float */
-void put_i32f(const STREAM *p, const int32_t num, const uint8_t places);
+void put_i32f(const STREAM *p, int32_t num, uint8_t places);
 
 
 /** Print CR LF */