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All devices on the PS 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.


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 n_sectors;
	char unused[8];

	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;
	char unused2[8];
	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 Mountpoint Physical Storage Holder Description
0x0 empty partition
0x1 "idstor" Internal Flash IdStorage
0x2 "sloader" Internal Flash SLB2 Boot loaders
0x3 "os" os0 Internal Flash Main OS partition, contains kernel modules
0x4 "vsh" vs0 Internal Flash System applications & libraries
0x5 "vshdata" vd0 Internal Flash Registry and error history
0x6 "vtrm" tm0 Internal Flash NpDrm, Marlin and DevKit/TestKit activations files
0x7 "user" ur0 Internal Flash User resources, LiveArea cache, database, & other stuff
0x8 "userext" ux0 Internal Flash / 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 Flash Updater application and PUP copied here before reboot
0xC "sysdata" sa0 Internal Flash Dictionary and font data
0xD "mediaid" Memory Card / Game Card Some data on Memory Card & Game Card
0xE "pidata" pd0 Internal Flash Welcome Park and welcome video (Partition not present in Prototype units)
0xF "unused" 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 System Software update, only the inactive partition is written to and finally the active partition is swapped. For partitions that do not use this activation feature, this value is ignored.