Partitions

All devices on the Vita are partitioned the same way. Logical block size is 512 bytes and the first logical block is the master block which defines the partition table along with other information. Because of block level encryption, the master block is also encrypted along with everything else and cannot be seen if the device is dumped from an external dumper.

Types

typedef struct SceMbrPartEntry { // size is 0x11-bytes
	unsigned int start_lba;
	unsigned int n_sectors;
	unsigned char id;
	unsigned char type;
	unsigned char flag;
	unsigned short acl;
	unsigned int unused;
} __attribute__((packed)) SceMbrPartEntry;

typedef struct SceMbrParts { // size is 0x110-bytes
	SceMbrPartEntry entries[0x10];
} __attribute__((packed)) SceMbrParts;

typedef struct SceMbr { // size is 0x200-bytes
	char magic[0x20];
	unsigned int version;
	unsigned int nSector;
	uint64_t unused;

	unsigned int loader_start;
	unsigned int loader_count;
	unsigned int current_bl_lba;
	unsigned int bl_bank0_lba;

	unsigned int bl_bank1_lba;
	unsigned int current_os_lba;
	uint64_t unused2;
	SceMbrParts parts;
	char unused3[0x6E]
	char unused4[0x30];
	unsigned short signature;
} __attribute__((packed)) SceMbr;

Master Block

The first block (512 bytes) provides a partition table as well as auxiliary information to the block management drivers.

Offset	Size	Information
0x0	0x20	magic. Magic string "Sony Computer Entertainment Inc."
0x20	0x4	version. Usually 3.
0x24	0x4	n_sectors. Size of device in blocks (ex: 0x70A000, 0x71A000: bigger ur0:)
0x28	0x8	unused.
0x30	0x4	loader_start. Second Loader (second_loader.enp) offset in blocks
0x34	0x4	loader_count. Second Loader (second_loader.enp) size in blocks
0x38	0x4	current_bl_lba. Active SLB2 offset in blocks (must be either bank0 or bank1)
0x3C	0x4	bl_bank0_lba. SLB2 bank0 offset in blocks (default: 0x4000)
0x40	0x4	bl_bank1_lba. SLB2 bank1 offset in blocks (default: 0x6000)
0x44	0x4	current_os_lba. Active os0 offset in blocks (ex: 0x8000, 0x10000)
0x48	0x8	unused.
0x50	0x110 (0x11 per partition * 0x10 partitions)	partition_table. Partition entries (there are 0x10 partitions at most (derived from code and data structure of SdStor driver))
0x160	0x9E	unused.
0x1FE	0x2	signature. MBR signature: 0xAA55

Partition Entries

Each partition entry is 17 bytes long.

Offset	Size	Information
0x0	0x4	start_lba. Partition offset (blocks)
0x4	0x4	n_sectors. Partition size (blocks)
0x8	0x1	part_id. Partition ID
0x9	0x1	part_type. Partition Type
0xA	0x1	part_flag. Partition Flag (boolean)
0xB	0x2	acl. Access control lists. Seen: 0x0555, 0x0F0F (sloader, os, vsh) -> r--, 0x0F1F (idstor) -> ---, 0x0F4F, 0x0FFF (sysdata, vtrm, vshdata, updater, pidata, user) -> rwx
0xF	0x4	unused

Partition ID

The Partition ID uniquely identifies the partition to its function. It is related to SceKernelModulemgr#Partition ID.

Partition ID	Block Device	Name	Location Seen	Description
0x0				empty partition
0x1	"idstor"		Internal	IdStorage
0x2	"sloader"		Internal	SLB2 Boot loaders
0x3	"os"	os0	Internal	Main OS partition, contains kernel modules
0x4	"vsh"	vs0	Internal	System applications & libraries
0x5	"vshdata"	vd0	Internal	Registry and error history
0x6	"vtrm"	tm0	Internal	NpDrm, Marlin and DevKit/TestKit activations files
0x7	"user"	ur0	Internal	User resources, LiveArea cache, database, & other stuff
0x8	"userext"	ux0	Internal / Memory Card	Memory Card
0x9	"gamero"	gro0	Game Card	Game Card read-only area
0xA	"gamerw"	grw0	Game Card	Game Card writable area
0xB	"updater"	ud0	Internal	Updater application and PUP copied here before reboot
0xC	"sysdata"	sa0	Internal	Dictionary and font data
0xD	"mediaid"		External	Some data on Memory Card & Game Card
0xE	"pidata"	pd0	Internal	Welcome Park and welcome video (Partition not present in Prototype units)
0xF	"unused"		External	Unknown

Partition Type

The partition type indicates the file system or if there is no file system (for example, in the case of a SLB2 archive).

Partition Type	Name
0x6	FAT16
0x7	exFAT
0xDA	Raw data

Partition Flag

Some partitions (specifically os0 and the boot loaders) have a shadow redundant copy. On update, only the inactive partition is written to and finally the active partition is swapped. For partitions that do not use this feature, this value is ignored.