diff --git a/gpttool/Android.mk b/gpttool/Android.mk
new file mode 100644
index 0000000..a9fffe9
--- /dev/null
+++ b/gpttool/Android.mk
@@ -0,0 +1,14 @@
+ifeq ($(HOST_OS),linux)
+
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := gpttool.c
+LOCAL_STATIC_LIBRARIES := libz
+
+LOCAL_MODULE := gpttool
+LOCAL_MODULE_TAGS := eng
+
+include $(BUILD_HOST_EXECUTABLE)
+
+endif
diff --git a/gpttool/gpttool.c b/gpttool/gpttool.c
new file mode 100644
index 0000000..6cb7c16
--- /dev/null
+++ b/gpttool/gpttool.c
@@ -0,0 +1,374 @@
+/* system/core/gpttool/gpttool.c
+**
+** Copyright 2011, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include <zlib.h>
+
+#include <linux/fs.h>
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+typedef unsigned long long u64;
+
+const u8 partition_type_uuid[16] = {
+	0xa2, 0xa0, 0xd0, 0xeb, 0xe5, 0xb9, 0x33, 0x44,
+	0x87, 0xc0, 0x68, 0xb6, 0xb7, 0x26, 0x99, 0xc7,
+};
+
+
+#define EFI_VERSION 0x00010000
+#define EFI_MAGIC "EFI PART"
+#define EFI_ENTRIES 128
+#define EFI_NAMELEN 36
+
+struct efi_header {
+	u8 magic[8];
+
+	u32 version;
+	u32 header_sz;
+
+	u32 crc32;
+	u32 reserved;
+
+	u64 header_lba;
+	u64 backup_lba;
+	u64 first_lba;
+	u64 last_lba;
+
+	u8 volume_uuid[16];
+
+	u64 entries_lba;
+
+	u32 entries_count;
+	u32 entries_size;
+	u32 entries_crc32;
+} __attribute__((packed));
+
+struct efi_entry {
+	u8 type_uuid[16];
+	u8 uniq_uuid[16];
+	u64 first_lba;
+	u64 last_lba;
+	u64 attr;
+	u16 name[EFI_NAMELEN];
+};
+
+struct ptable {
+	u8 mbr[512];
+	union {
+		struct efi_header header;
+		u8 block[512];
+	};
+	struct efi_entry entry[EFI_ENTRIES];	
+};
+
+void get_uuid(u8 *uuid)
+{
+	int fd;
+	fd = open("/dev/urandom", O_RDONLY);
+	read(fd, uuid, 16);
+	close(fd);
+}
+
+void init_mbr(u8 *mbr, u32 blocks)
+{
+	mbr[0x1be] = 0x00; // nonbootable
+	mbr[0x1bf] = 0xFF; // bogus CHS
+	mbr[0x1c0] = 0xFF;
+	mbr[0x1c1] = 0xFF;
+
+	mbr[0x1c2] = 0xEE; // GPT partition
+	mbr[0x1c3] = 0xFF; // bogus CHS
+	mbr[0x1c4] = 0xFF;
+	mbr[0x1c5] = 0xFF;
+
+	mbr[0x1c6] = 0x01; // start
+	mbr[0x1c7] = 0x00;
+	mbr[0x1c8] = 0x00;
+	mbr[0x1c9] = 0x00;
+
+	memcpy(mbr + 0x1ca, &blocks, sizeof(u32));
+
+	mbr[0x1fe] = 0x55;
+	mbr[0x1ff] = 0xaa;
+}
+
+int add_ptn(struct ptable *ptbl, u64 first, u64 last, const char *name)
+{
+	struct efi_header *hdr = &ptbl->header;
+	struct efi_entry *entry = ptbl->entry;
+	unsigned n;
+
+	if (first < 34) {
+		fprintf(stderr,"partition '%s' overlaps partition table\n", name);
+		return -1;
+	}
+
+	if (last > hdr->last_lba) {
+		fprintf(stderr,"partition '%s' does not fit on disk\n", name);
+		return -1;
+	}
+	for (n = 0; n < EFI_ENTRIES; n++, entry++) {
+		if (entry->type_uuid[0])
+			continue;
+		memcpy(entry->type_uuid, partition_type_uuid, 16);
+		get_uuid(entry->uniq_uuid);
+		entry->first_lba = first;
+		entry->last_lba = last;
+		for (n = 0; (n < EFI_NAMELEN) && *name; n++)
+			entry->name[n] = *name++;
+		return 0;
+	}
+	fprintf(stderr,"out of partition table entries\n");
+	return -1;
+}
+
+int usage(void)
+{
+	fprintf(stderr,
+		"usage: gpttool write <disk> [ <partition> ]*\n"
+		"       gpttool read <disk>\n"
+		"       gpttool test [ <partition> ]*\n"
+		"\n"
+		"partition:  [<name>]:<size>[kmg] | @<file-of-partitions>\n"
+		);
+	return 0;
+}
+
+void show(struct ptable *ptbl)
+{
+	struct efi_entry *entry = ptbl->entry;
+	unsigned n, m;
+	char name[EFI_NAMELEN];
+
+	fprintf(stderr,"ptn  start block   end block     name\n");
+	fprintf(stderr,"---- ------------- ------------- --------------------\n");
+
+	for (n = 0; n < EFI_ENTRIES; n++, entry++) {
+		if (entry->type_uuid[0] == 0)
+			break;
+		for (m = 0; m < EFI_NAMELEN; m++) {
+			name[m] = entry->name[m] & 127;
+		}
+		name[m] = 0;
+		fprintf(stderr,"#%03d %13lld %13lld %s\n",
+			n + 1, entry->first_lba, entry->last_lba, name);
+	}
+}
+
+u64 find_next_lba(struct ptable *ptbl)
+{
+	struct efi_entry *entry = ptbl->entry;
+	unsigned n;
+	u64 a = 0;
+	for (n = 0; n < EFI_ENTRIES; n++, entry++) {
+		if ((entry->last_lba + 1) > a)
+			a = entry->last_lba + 1;
+	}
+	return a;
+}
+
+u64 next_lba = 0;
+
+u64 parse_size(char *sz)
+{
+	int l = strlen(sz);
+	u64 n = strtoull(sz, 0, 10);
+	if (l) {
+		switch(sz[l-1]){
+		case 'k':
+		case 'K':
+			n *= 1024;
+			break;
+		case 'm':
+		case 'M':
+			n *= (1024 * 1024);
+			break;
+		case 'g':
+		case 'G':
+			n *= (1024 * 1024 * 1024);
+			break;
+		}
+	}
+	return n;
+}
+
+int parse_ptn(struct ptable *ptbl, char *x)
+{
+	char *y = strchr(x, ':');
+	u64 sz;
+
+	if (!y) {
+		fprintf(stderr,"invalid partition entry: %s\n", x);
+		return -1;
+	}
+	*y++ = 0;
+
+	if (*y == 0) {
+		sz = ptbl->header.last_lba - next_lba;
+	} else {
+		sz = parse_size(y);
+		if (sz & 511) {
+			fprintf(stderr,"partition size must be multiple of 512\n");
+			return -1;
+		}
+		sz /= 512;
+	}
+
+	if (sz == 0) {
+		fprintf(stderr,"zero size partitions not allowed\n");
+		return -1;
+	}
+
+	if (x[0] && add_ptn(ptbl, next_lba, next_lba + sz - 1, x))
+		return -1;
+
+	next_lba = next_lba + sz;
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	struct ptable ptbl;
+	struct efi_entry *entry;
+	struct efi_header *hdr = &ptbl.header;
+	struct stat s;
+	u32 n;
+	u64 sz, blk;
+	int fd;
+	const char *device;
+	int real_disk = 0;
+
+	if (argc < 2)
+		return usage();
+
+	if (!strcmp(argv[1], "write")) {
+		if (argc < 3)
+			return usage();
+		device = argv[2];
+		argc -= 2;
+		argv += 2;
+		real_disk = 1;
+	} else if (!strcmp(argv[1], "test")) {
+		argc -= 1;
+		argv += 1;
+		real_disk = 0;
+		sz = 2097152 * 16;
+		fprintf(stderr,"< simulating 16GB disk >\n\n");
+	} else {
+		return usage();
+	}
+
+	if (real_disk) {
+		if (!strcmp(device, "/dev/sda") || 
+		    !strcmp(device, "/dev/sdb")) {
+			fprintf(stderr,"error: refusing to partition sda or sdb\n");
+			return -1;
+		}
+		
+		fd = open(device, O_RDWR);
+		if (fd < 0) {
+			fprintf(stderr,"error: cannot open '%s'\n", device);
+			return -1;
+		}
+		if (ioctl(fd, BLKGETSIZE64, &sz)) {
+			fprintf(stderr,"error: cannot query block device size\n");
+			return -1;
+		}
+		sz /= 512;
+		fprintf(stderr,"blocks %lld\n", sz);
+	}
+
+	memset(&ptbl, 0, sizeof(ptbl));
+
+	init_mbr(ptbl.mbr, sz - 1);
+
+	memcpy(hdr->magic, EFI_MAGIC, sizeof(hdr->magic));
+	hdr->version = EFI_VERSION;
+	hdr->header_sz = sizeof(struct efi_header);
+	hdr->header_lba = 1;
+	hdr->backup_lba = sz - 1;
+	hdr->first_lba = 34;
+	hdr->last_lba = sz - 1;
+	get_uuid(hdr->volume_uuid);
+	hdr->entries_lba = 2;
+	hdr->entries_count = 128;
+	hdr->entries_size = sizeof(struct efi_entry);
+
+	while (argc > 1) {
+		if (argv[1][0] == '@') {
+			char line[256], *p;
+			FILE *f;
+			f = fopen(argv[1] + 1, "r");
+			if (!f) {
+				fprintf(stderr,"cannot read partitions from '%s\n", argv[1]);
+				return -1;
+			}
+			while (fgets(line, sizeof(line), f)) {
+				p = line + strlen(line);
+				while (p > line) {
+					p--;
+					if (*p > ' ')
+						break;
+					*p = 0;
+				}
+				p = line;
+				while (*p && (*p <= ' '))
+					p++;
+				if (*p == '#')
+					continue;
+				if (*p == 0)
+					continue;
+				if (parse_ptn(&ptbl, p))
+					return -1;
+			}
+			fclose(f);
+		} else {	
+			if (parse_ptn(&ptbl, argv[1]))
+				return -1;
+		}
+		argc--;
+		argv++;
+	}
+
+	n = crc32(0, Z_NULL, 0);
+	n = crc32(n, (void*) ptbl.entry, sizeof(ptbl.entry));
+	hdr->entries_crc32 = n;
+
+	n = crc32(0, Z_NULL, 0);
+	n = crc32(n, (void*) &ptbl.header, sizeof(ptbl.header));
+	hdr->crc32 = n;
+
+	show(&ptbl);
+
+	if (real_disk) {
+  		write(fd, &ptbl, sizeof(ptbl));
+		fsync(fd);
+
+		if (ioctl(fd, BLKRRPART, 0)) {
+			fprintf(stderr,"could not re-read partition table\n");
+		}
+		close(fd);
+	}
+	return 0;
+}