diff --git a/Makefile b/Makefile
index 5f6f947..0445192 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 PREFIX = /usr/local
 TARGETLIBS = libfdt.a
-LIBOBJS = fdt.o fdt_ro.o fdt_wip.o #fdt_sw.o
+LIBOBJS = fdt.o fdt_ro.o fdt_wip.o fdt_sw.o
 
 SOURCE = $(shell find . -maxdepth 1 ! -name version.h -a -name '*.[h]')
 SOURCE += *.c Makefile
diff --git a/fdt_ro.c b/fdt_ro.c
index bfd8163..43a79e5 100644
--- a/fdt_ro.c
+++ b/fdt_ro.c
@@ -25,12 +25,24 @@
 
 static int check_header(const struct fdt_header *fdt)
 {
-	if (fdt32_to_cpu(fdt->magic) != FDT_MAGIC)
+	uint32_t magic = fdt32_to_cpu(fdt->magic);
+	uint32_t version = fdt32_to_cpu(fdt->version);
+	uint32_t last_comp_version = fdt32_to_cpu(fdt->last_comp_version);
+
+	if (magic == FDT_MAGIC) {
+		/* Complete tree */
+		if (version < FDT_FIRST_SUPPORTED_VERSION)
+			return FDT_ERR_BADVERSION;
+		if (last_comp_version > FDT_LAST_SUPPORTED_VERSION)
+			return FDT_ERR_BADVERSION;
+	} else if (magic == SW_MAGIC) {
+		/* Unfinished sequential-write blob */
+		if (SW_SIZE_DT_STRUCT(fdt) == 0)
+			return FDT_ERR_BADSTATE;
+	} else {
 		return FDT_ERR_BADMAGIC;
-	if (fdt32_to_cpu(fdt->version) < FDT_FIRST_SUPPORTED_VERSION)
-		return FDT_ERR_BADVERSION;
-	if (fdt32_to_cpu(fdt->last_comp_version) > FDT_LAST_SUPPORTED_VERSION)
-		return FDT_ERR_BADVERSION;
+	}
+
 	return 0;
 }
 
diff --git a/fdt_sw.c b/fdt_sw.c
new file mode 100644
index 0000000..84a38d8
--- /dev/null
+++ b/fdt_sw.c
@@ -0,0 +1,236 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "libfdt_env.h"
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+static int check_header_sw(struct fdt_header *fdt)
+{
+	if (fdt32_to_cpu(fdt->magic) != SW_MAGIC)
+		return FDT_ERR_BADMAGIC;
+	return 0;
+}
+
+static void *grab_space(struct fdt_header *fdt, int len)
+{
+	int off_dt_struct = fdt32_to_cpu(fdt->off_dt_struct);
+	int offset = fdt32_to_cpu(SW_SIZE_DT_STRUCT(fdt));
+	int spaceleft;
+
+	spaceleft = fdt32_to_cpu(fdt->totalsize) - off_dt_struct
+		- fdt32_to_cpu(fdt->size_dt_strings);
+
+	if ((offset + len < offset) || (offset + len > spaceleft))
+		return NULL;
+
+	SW_SIZE_DT_STRUCT(fdt) = cpu_to_fdt32(offset + len);
+	return fdt_offset_ptr(fdt, offset, len);
+}
+
+struct fdt_header *fdt_create(void *buf, int bufsize)
+{
+	struct fdt_header *fdt = buf;
+
+	if (bufsize < sizeof(struct fdt_header))
+		return NULL;
+
+	memset(buf, 0, bufsize);
+
+	fdt->magic = cpu_to_fdt32(SW_MAGIC);
+	fdt->totalsize = cpu_to_fdt32(bufsize);
+
+	fdt->off_mem_rsvmap = cpu_to_fdt32(ALIGN(sizeof(*fdt),
+						 sizeof(struct fdt_reserve_entry)));
+	fdt->off_dt_struct = fdt->off_mem_rsvmap;
+	fdt->off_dt_strings = fdt32_to_cpu(bufsize);
+
+	return fdt;
+}
+
+int fdt_add_reservemap_entry(struct fdt_header *fdt, uint64_t addr, uint64_t size)
+{
+	struct fdt_reserve_entry *re;
+	int err = check_header_sw(fdt);
+	int offset;
+
+	if (err)
+		return err;
+	if (SW_SIZE_DT_STRUCT(fdt))
+		return FDT_ERR_BADSTATE;
+
+	offset = fdt32_to_cpu(fdt->off_dt_struct);
+	if ((offset + sizeof(*re)) > fdt32_to_cpu(fdt->totalsize))
+		return FDT_ERR_NOSPACE;
+
+	re = (struct fdt_reserve_entry *)((void *)fdt + offset);
+	re->address = cpu_to_fdt64(addr);
+	re->size = cpu_to_fdt64(size);
+
+	fdt->off_dt_struct = cpu_to_fdt32(offset + sizeof(*re));
+
+	return 0;
+}
+
+int fdt_finish_reservemap(struct fdt_header *fdt)
+{
+	return fdt_add_reservemap_entry(fdt, 0, 0);
+}
+
+int fdt_begin_node(struct fdt_header *fdt, const char *name)
+{
+	struct fdt_node_header *nh;
+	int err = check_header_sw(fdt);
+	int namelen = strlen(name) + 1;
+
+	if (err)
+		return err;
+
+	nh = grab_space(fdt, sizeof(*nh) + ALIGN(namelen, FDT_TAGSIZE));
+	if (! nh)
+		return FDT_ERR_NOSPACE;
+
+	nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
+	memcpy(nh->name, name, namelen);
+	return 0;
+}
+
+int fdt_end_node(struct fdt_header *fdt)
+{
+	uint32_t *en;
+	int err = check_header_sw(fdt);
+
+	if (err)
+		return err;
+
+	en = grab_space(fdt, FDT_TAGSIZE);
+	if (! en)
+		return FDT_ERR_NOSPACE;
+
+	*en = cpu_to_fdt32(FDT_END_NODE);
+	return 0;
+}
+
+static int find_add_string(struct fdt_header *fdt, const char *s)
+{
+	int totalsize = fdt32_to_cpu(fdt->totalsize);
+	char *strtab = (char *)fdt + totalsize;
+	int strtabsize = fdt32_to_cpu(fdt->size_dt_strings);
+	int len = strlen(s) + 1;
+	int struct_top, offset;
+
+	/* We treat string offsets as negative from the end of our buffer */
+	/* then fix them up in fdt_finish() */
+	offset = -strtabsize;
+	while ((offset < 0) && (memcmp(strtab + offset, s, len) != 0))
+		offset++;
+
+	if (offset < 0)
+		/* Found it */
+		return offset;
+
+	/* Add it */
+	offset = -strtabsize - len;
+	struct_top = fdt32_to_cpu(fdt->off_dt_struct)
+		+ fdt32_to_cpu(SW_SIZE_DT_STRUCT(fdt));
+	if (totalsize + offset < struct_top)
+		return 0; /* no more room :( */
+
+	memcpy(strtab + offset, s, len);
+	fdt->size_dt_strings = cpu_to_fdt32(strtabsize + len);
+	return offset;
+}
+
+int fdt_property(struct fdt_header *fdt, const char *name, const void *val, int len)
+{
+	struct fdt_property *prop;
+	int err = check_header_sw(fdt);
+	int nameoff;
+
+	if (err)
+		return err;
+
+	nameoff = find_add_string(fdt, name);
+	if (nameoff == 0)
+		return FDT_ERR_NOSPACE;
+
+	prop = grab_space(fdt, sizeof(*prop) + ALIGN(len, FDT_TAGSIZE));
+	if (! prop)
+		return FDT_ERR_NOSPACE;
+
+	prop->tag = cpu_to_fdt32(FDT_PROP);
+	prop->nameoff = cpu_to_fdt32(nameoff);
+	prop->len = cpu_to_fdt32(len);
+	memcpy(prop->data, val, len);
+	return 0;
+}
+
+int fdt_finish(struct fdt_header *fdt)
+{
+	int err = check_header_sw(fdt);
+	char *p = (char *)fdt;
+	uint32_t *end;
+	int oldstroffset, newstroffset, strsize;
+	uint32_t tag;
+	int offset, nextoffset;
+
+	if (err)
+		return err;
+
+	/* Add terminator */
+	end = grab_space(fdt, sizeof(*end));
+	if (! end)
+		return FDT_ERR_NOSPACE;
+	*end = cpu_to_fdt32(FDT_END);
+
+	/* Relocate the string table */
+	strsize = fdt32_to_cpu(fdt->size_dt_strings);
+	oldstroffset = fdt32_to_cpu(fdt->totalsize) - strsize;
+	newstroffset = fdt32_to_cpu(fdt->off_dt_struct)
+		+ fdt32_to_cpu(SW_SIZE_DT_STRUCT(fdt));
+	memmove(p + newstroffset, p + oldstroffset, strsize);
+	fdt->off_dt_strings = fdt32_to_cpu(newstroffset);
+
+	/* Walk the structure, correcting string offsets */
+	offset = 0;
+	while ((tag = _fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
+		if (tag == FDT_PROP) {
+			struct fdt_property *prop = fdt_offset_ptr(fdt, offset,
+								   sizeof(*prop));
+			int nameoff;
+
+			if (! prop)
+				return FDT_ERR_BADSTRUCTURE;
+
+			nameoff = fdt32_to_cpu(prop->nameoff);
+			nameoff += strsize;
+			prop->nameoff = cpu_to_fdt32(nameoff);
+		}
+		offset = nextoffset;
+	}
+
+	/* Finally, adjust the header */
+	fdt->totalsize = cpu_to_fdt32(newstroffset + strsize);
+	fdt->version = cpu_to_fdt32(FDT_LAST_SUPPORTED_VERSION);
+	fdt->last_comp_version= cpu_to_fdt32(FDT_FIRST_SUPPORTED_VERSION);
+	fdt->magic = cpu_to_fdt32(FDT_MAGIC);
+	return 0;
+}
diff --git a/libfdt.h b/libfdt.h
index 605aa89..b58ae0f 100644
--- a/libfdt.h
+++ b/libfdt.h
@@ -82,16 +82,23 @@ int fdt_setprop_inplace(struct fdt_header *fdt, int nodeoffset, const char *name
 int fdt_nop_property(struct fdt_header *fdt, int nodeoffset, const char *name);
 int fdt_nop_node(struct fdt_header *fdt, int nodeoffset);
 
-#if 0
 /* Sequential-write functions */
 struct fdt_header *fdt_create(void *buf, int bufsize);
 int fdt_add_reservemap_entry(struct fdt_header *fdt, uint64_t addr, uint64_t size);
-int fdt_begin_structure(struct fdt_header *fdt);
+int fdt_finish_reservemap(struct fdt_header *fdt);
 int fdt_begin_node(struct fdt_header *fdt, const char *name);
 int fdt_property(struct fdt_header *fdt, const char *name, const void *val, int len);
+#define fdt_property_typed(fdt, name, val) \
+	({ \
+		typeof(val) x = (val); \
+		fdt_property((fdt), (name), &x, sizeof(x)); \
+	})
+#define fdt_property_string(fdt, name, str) \
+	fdt_property(fdt, name, str, strlen(str)+1)
 int fdt_end_node(struct fdt_header *fdt);
-int fdt_finish_structure(struct fdt_header *fdt);
+int fdt_finish(struct fdt_header *fdt);
 
+#if 0
 /* Read-write functions */
 struct fdt_header *fdt_open(struct fdt_header *fdt, int bufsize);
 int fdt_add_subnode(struct fdt_header *fdtx, void *node, const char *name);
diff --git a/libfdt_internal.h b/libfdt_internal.h
index 1f9ba0c..0bc2786 100644
--- a/libfdt_internal.h
+++ b/libfdt_internal.h
@@ -34,6 +34,7 @@ struct fdt_property *_fdt_getprop(const struct fdt_header *fdt, int nodeoffset,
 #define OFFSET_ERROR(code)	-(code)
 #define PTR_ERROR(code)		(void *)(-(code))
 
-#define SW_OFFSET(fdt)		((fdt)->version)
+#define SW_MAGIC		(~FDT_MAGIC)
+#define SW_SIZE_DT_STRUCT(fdt)	((fdt)->version)
 
 #endif /* _LIBFDT_INTERNAL_H */
diff --git a/tests/Makefile b/tests/Makefile
index 2b165dc..b6dc852 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -2,7 +2,8 @@ PREFIX = /usr/local
 
 LIB_TESTS = root_node property_offset subnode_offset path_offset getprop \
 	notfound \
-	setprop_inplace nop_property nop_node
+	setprop_inplace nop_property nop_node \
+	sw_tree1
 TESTS = $(LIB_TESTS)
 UTILS = dumptrees
 
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 0ffdc93..338e47a 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -27,7 +27,15 @@ tree1_tests () {
 }
 
 functional_tests () {
+    # Make sure we don't have stale blobs lying around
+    rm -f *.test.dtb
+
     tree1_tests test_tree1.dtb
+
+    # Sequential write tests
+    run_test sw_tree1
+    tree1_tests sw_tree1.test.dtb
+    tree1_tests unfinished_tree1.test.dtb
 }
 
 stress_tests () {
diff --git a/tests/sw_tree1.c b/tests/sw_tree1.c
new file mode 100644
index 0000000..6f72006
--- /dev/null
+++ b/tests/sw_tree1.c
@@ -0,0 +1,83 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ *	Testcase for fdt_nop_node()
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "tests.h"
+#include "testdata.h"
+
+#define SPACE	65536
+
+#define CHECK(code) \
+	{ \
+		err = (code); \
+		if (err) \
+			FAIL(#code ": %s", fdt_strerror(err)); \
+	}
+
+int main(int argc, char *argv[])
+{
+	void *buf;
+	struct fdt_header *fdt;
+	int err;
+
+	test_init(argc, argv);
+
+	buf = xmalloc(SPACE);
+	fdt = fdt_create(buf, SPACE);
+
+	CHECK(fdt_finish_reservemap(fdt));
+	CHECK(fdt_begin_node(fdt, ""));
+	CHECK(fdt_property_typed(fdt, "prop-int", TEST_VALUE_1));
+	CHECK(fdt_property_string(fdt, "prop-str", TEST_STRING_1));
+
+	CHECK(fdt_begin_node(fdt, "subnode1"));
+	CHECK(fdt_property_typed(fdt, "prop-int", TEST_VALUE_1));
+	CHECK(fdt_begin_node(fdt, "subsubnode"));
+	CHECK(fdt_property_typed(fdt, "prop-int", TEST_VALUE_1));
+	CHECK(fdt_end_node(fdt));
+	CHECK(fdt_end_node(fdt));
+
+	CHECK(fdt_begin_node(fdt, "subnode2"));
+	CHECK(fdt_property_typed(fdt, "prop-int", TEST_VALUE_2));
+	CHECK(fdt_begin_node(fdt, "subsubnode"));
+	CHECK(fdt_property_typed(fdt, "prop-int", TEST_VALUE_2));
+	CHECK(fdt_end_node(fdt));
+	CHECK(fdt_end_node(fdt));
+
+	CHECK(fdt_end_node(fdt));
+
+	save_blob("unfinished_tree1.test.dtb", fdt);
+
+	CHECK(fdt_finish(fdt));
+
+	verbose_printf("Completed tree, totalsize = %d\n",
+		       fdt32_to_cpu(fdt->totalsize));
+
+	save_blob("sw_tree1.test.dtb", fdt);
+
+	PASS();
+}
diff --git a/tests/tests.h b/tests/tests.h
index b5fd475..64ab64f 100644
--- a/tests/tests.h
+++ b/tests/tests.h
@@ -139,5 +139,6 @@ void *check_getprop(struct fdt_header *fdt, int nodeoffset, const char *name,
 	})
 //void *load_blob(const char *filename);
 void *load_blob_arg(int argc, char *argv[]);
+void save_blob(const char *filename, struct fdt_header *fdt);
 
 #endif /* _TESTS_H */
diff --git a/tests/testutils.c b/tests/testutils.c
index af8c2ad..4997a8e 100644
--- a/tests/testutils.c
+++ b/tests/testutils.c
@@ -202,3 +202,29 @@ void *load_blob_arg(int argc, char *argv[])
 		CONFIG("Usage: %s <dtb file>", argv[0]);
 	return load_blob(argv[1]);
 }
+
+void save_blob(const char *filename, struct fdt_header *fdt)
+{
+	int fd;
+	int totalsize;
+	int offset;
+	void *p;
+	int ret;
+
+	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (fd < 0)
+		CONFIG("Couldn't open \"%s\" to write blob: %s", filename,
+		       strerror(errno));
+
+	totalsize = fdt32_to_cpu(fdt->totalsize);
+	offset = 0;
+	p = fdt;
+
+	while (offset < totalsize) {
+		ret = write(fd, p + offset, totalsize - offset);
+		if (ret < 0)
+			CONFIG("Couldn't write to \"%s\": %s", filename,
+			       strerror(errno));
+		offset += ret;
+	}
+}