Index: libparted/labels/gpt.c
===================================================================
--- libparted/labels/gpt.c.orig
+++ libparted/labels/gpt.c
@@ -46,6 +46,8 @@
 #  define _(String) (String)
 #endif				/* ENABLE_NLS */
 
+#define GPT_SYNC_MBR
+
 #define EFI_PMBR_OSTYPE_EFI 0xEE
 #define MSDOS_MBR_SIGNATURE 0xaa55
 
@@ -402,6 +404,7 @@ guid_cmp (efi_guid_t left, efi_guid_t ri
 	return memcmp(&left, &right, sizeof(efi_guid_t));
 }
 
+#ifndef GPT_SYNC_MBR
 /* checks if 'mbr' is a protective MBR partition table */
 static inline int
 _pmbr_is_valid (const LegacyMBR_t* mbr)
@@ -418,6 +421,7 @@ _pmbr_is_valid (const LegacyMBR_t* mbr)
 	}
 	return 0;
 }
+#endif
 
 static int
 gpt_probe (const PedDevice * dev)
@@ -445,6 +449,7 @@ gpt_probe (const PedDevice * dev)
 	if (!gpt_sig_found)
 		return 0;
 
+#ifndef GPT_SYNC_MBR
 	if (ped_device_read(dev, &legacy_mbr, 0, GPT_HEADER_SECTORS)) {
 		if (!_pmbr_is_valid (&legacy_mbr)) {
 			int ex_status = ped_exception_throw (
@@ -463,6 +468,7 @@ gpt_probe (const PedDevice * dev)
 				return 0;
 		}
 	}
+#endif
 
 	return 1;
 }
@@ -928,15 +934,51 @@ error:
 	return 0;
 }
 
+#ifdef GPT_SYNC_MBR
+static inline unsigned char
+_part_to_ostype (PedPartition* part)
+{
+	GPTPartitionData* gpt_part_data = part->disk_specific;
+	if (part->fs_type) {
+		if (strncmp (part->fs_type->name, "fat", 3) == 0) return 0xc;
+		if (strncmp (part->fs_type->name, "ntfs", 4) == 0) return 0x7;
+		if (strncmp (part->fs_type->name, "hfs", 3) == 0) return 0xaf;
+		if (strstr (part->fs_type->name, "swap")) return 0x82;
+	}
+	return 0x83; // Everything else is Linux
+}
+
+static inline uint32_t
+_part_32bitmax (uint64_t in)
+{
+	if (in > 0xFFFFFFFFULL) 
+		return 0xFFFFFFFF;
+	else
+		return (uint32_t)in;
+}
+#endif
+
 #ifndef DISCOVER_ONLY
 /* Writes the protective MBR (to keep DOS happy) */
 static int
-_write_pmbr (PedDevice * dev)
+_write_pmbr (PedDisk * disk)
 {
+	PedDevice * dev = disk->dev;
 	LegacyMBR_t pmbr;
+#ifdef GPT_SYNC_MBR
+	int i;
+	PedPartition* part = NULL;
+#endif
 
+#ifdef GPT_SYNC_MBR
+	/* Keep the old MBR as much as possible */
+	ped_device_read(dev, &pmbr, 0, GPT_HEADER_SECTORS);
+	memset(&pmbr.PartitionRecord, 0, sizeof(pmbr.PartitionRecord));
+#else
 	memset(&pmbr, 0, sizeof(pmbr));
+#endif
 	pmbr.Signature = PED_CPU_TO_LE16(MSDOS_MBR_SIGNATURE);
+#ifndef GPT_SYNC_MBR
 	pmbr.PartitionRecord[0].OSType      = EFI_PMBR_OSTYPE_EFI;
 	pmbr.PartitionRecord[0].StartSector = 1;
 	pmbr.PartitionRecord[0].EndHead     = 0xFE;
@@ -947,6 +989,31 @@ _write_pmbr (PedDevice * dev)
 		pmbr.PartitionRecord[0].SizeInLBA = PED_CPU_TO_LE32(0xFFFFFFFF);
 	else
 		pmbr.PartitionRecord[0].SizeInLBA = PED_CPU_TO_LE32(dev->length - 1UL);
+#else
+	/* sync the first 4 GPT entries to MBR primary partitions */
+	for (i=0; i < 4; i++) {
+		part = ped_disk_next_partition (disk, part);
+		if (part == NULL)
+			break;
+		/* we might get a starting garbage partition */
+		if (part->geom.start == 0 || part->type == PED_PARTITION_METADATA || part->type == PED_PARTITION_FREESPACE) {
+			i--;
+			continue;
+		}
+		pmbr.PartitionRecord[i].OSType      = _part_to_ostype(part);
+		pmbr.PartitionRecord[i].StartSector = 1;
+		pmbr.PartitionRecord[i].StartHead     = 0xFE;
+		pmbr.PartitionRecord[i].StartSector   = 0xFF;
+		pmbr.PartitionRecord[i].StartTrack    = 0xFF;
+		pmbr.PartitionRecord[i].EndHead     = 0xFE;
+		pmbr.PartitionRecord[i].EndSector   = 0xFF;
+		pmbr.PartitionRecord[i].EndTrack    = 0xFF;
+		pmbr.PartitionRecord[i].StartingLBA = _part_32bitmax(part->geom.start);
+		if(((GPTPartitionData*)part->disk_specific)->boot)
+			pmbr.PartitionRecord[i].BootIndicator = 0x80;
+		pmbr.PartitionRecord[i].SizeInLBA = _part_32bitmax(part->geom.end - part->geom.start);
+	}
+#endif
 
 	return ped_device_write (dev, &pmbr, GPT_PMBR_LBA, GPT_PMBR_SECTORS);
 }
@@ -1050,7 +1117,7 @@ gpt_write(const PedDisk * disk)
 	ptes_crc = efi_crc32 (ptes, ptes_size);
 
 	/* Write protective MBR */
-	if (!_write_pmbr (disk->dev))
+	if (!_write_pmbr (disk))
 		goto error_free_ptes;
 
 	/* Write PTH and PTEs */