PUP

PUP files are update archives for the Vita.

PUP Structure

A good resource on the PUP structure can be found HERE.

Update .PKG files

Most of the files in the update PUP are .pkg files, a sort of Certified File.

Each component of the update is broken up into multiple parts, then optionally compressed, and finally encrypted into the PKG.

Package Header

Right after the Certified File header (usually at offset 0x400) is the update package header that provides information for piecing the component back together. The contents of this header is as follows:

Offset	Size	Description
0x0	0x4	Version (0x4)
0x4	0x4	Type ID
0x8	0x4	Flags
0xC	0x4	?
0x10	0x8	Update FW Version
0x18	0x8	Final (decompressed) size
0x20	0x8	Decrypted size
0x28	0x8	?
0x30	0x4	?
0x34	0x4	?
0x38	0xC	?
0x3C	0x4	?
0x40	0x8	?
0x48	0x8	?
0x50	0x8	Offset
0x58	0x8	Size
0x60	0x8	Part Index
0x68	0x8	Total Parts
0x70	0x8	?
0x78	0x8	?

Flags

There are flags that are set in the package header. Some potential ones are listed here.

Flag	Description
0x10	Set when compressed
0x2	Has multiple parts
0x1	Set when compressed

Type ID

The type id determines which decryption routine to use in SceSblSsUpdateMgr. There is a truth table to determine which id can be handled by which decryption function. To see how this table is used, check out the example code for decrypting packages.

Type ID	Func 1?	Func 2?	Func 3?
0x0	No	No	No
0x1	Yes	Yes	No
0x2	No	No	No
0x3	No	No	Yes
0x4	No	No	Yes
0x5	No	No	No
0x6	No	No	No
0x7	No	No	No
0x8	Yes	Yes	No
0x9	Yes	Yes	No
0xA	Yes	Yes	Yes
0xB	Yes	Yes	No
0xC	Yes	Yes	No
0xD	Yes	Yes	No
0xE	No	No	No
0xF	Yes	Yes	No
0x10	Yes	Yes	No
0x11	Yes	Yes	No
0x12	Yes	Yes	No
0x13	Yes	Yes	No
0x14	Yes	Yes	No
0x15	Yes	Yes	Yes
0x16	Yes	Yes	Yes
0x17	Yes	Yes	Yes
0x18	Yes	Yes	No
0x19	Yes	Yes	No
0x1A	No	No	No
0x1B	No	No	Yes

Type ID (Identifier)

The type ID is also used to identify the component of the update.

Type ID	Note
0x0
0x1	os0 partition
0x2
0x3
0x4	Permissions related to TAR archives of type 0x16
0x5
0x6
0x7
0x8	Syscon Update (0x9A54 type)
0x9	SLB2 bootloaders
0xA	vs0 partition
0xB	Development CP firmware (same file as PUP entry 0x2006)
0xC	Motion related
0xD	Bbmc related
0xE
0xF	Motion related
0x10	Touch/Syscon related
0x11	Touch related
0x12	Syscon related
0x13	Syscon related
0x14	Syscon Update (0x3665 type)
0x15
0x16	TAR archive, patch update for vs0
0x17	sa0 partition
0x18	pd0 partition
0x19	Syscon Update (0xC5E7 type)
0x1A
0x1B	PSP Emulator lists

SCEWM

Header

This is a watermark for PUPs. For development PUPs, the Issue ID is unique to the company/organization the PUP is issued to.

Offset	Size	Description
0x0	0x6	Magic ('SCEWM\0')
0x6	0x2	?Version? (ex: 00 01)
0x8	0x4	Unknown (ex: 01 00 00 00)
0xC	0x4	Content size including RSA area (ex: 0x1000)
0x10	0x4	Issue ID (ex: 0xD9)
0x14	0x4	Unknown (ex: 01 00 00 00)
0x18	0x4	Unknown (ex: 01 00 00 00)
0x1C	0x4	Unknown (ex: 01 00 00 00)

The Issue ID for SCE/retail PUPs seems to be 0x5A.

Content

The SCEWM file is composed of 3 parts:

• SCEWM header: size 0x20 bytes.
• RSA2048 signature of the PUP (regardless of the watermark): size 0x100 bytes. This part IS NOT ENCRYPTED.
• SCEWM body (unique data per issue ID): size = file_size(usually 0x1000) - header_size(0x20) - pup_sig_size(0x100). Its size may vary, check file_size in SCEWM header. This part IS ENCRYPTED.

Body

The body is encrypted using AES128CBC with key and iv from update_service_sm.self.

After decryption, the data is composed of 2 parts:

• 0xDE0 bytes: plaintext ASCII message
• 0x100 bytes: RSA2048 signature of that message

Message

The message is generated on developer demand by DevNet server. The message syntax has changed with DevNet revisions.

The message is totally independant of the PUP. The same PUP (for example PSVita FW 0.945) downloaded from DevNet in 2011 and in 2018 has different message syntax.

Here 'x' represents an actual character, which I hide for confidentiality.

Old message (2011-02)

# PUP watermark data that contain DevNet user id, org name, company name, date of PUP downloaded and host IP address
User id:xxxxxx
Org name:xxxxxxxxxxxxxx
Company name:xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Date PUP downloaded:xxxx-xx-xx xx:xx
Host IP address:xxx.xxx.xxx.xxx

Recent message (2018-04)

# PUP watermark data contain a serial_number that associates with the user who download this PUP
# Provide the serial number below to the DevNet development team to get user and org details.
PUP serial number:xxxxxxxx

Signature

It is RSA2048 of the watermark + maybe other data.

Security

When comparing same PUP signed for two different issue IDs, we can notice only 2 differences:

• the issue ID in SCEWM header
• the SCEWM unique data

SCEAS

This file contains Additional Signatures (A.S.) necessary for validation of the PUP.

It was added in FW 0.996, probably for security reasons.

This file is missing inside the DEX PUP v 0.945.040 (and all the pre-0.996 pups)

Header

Offset	Size	Description
0x0	0x6	Magic ('SCEAS\0')
0x6	0x2	?Version? (ex: 00 01)
0xC	0x4	File Size (usually 0x400)
0x10	0x4	Unknown
0x14	0x4	Unknown
0x18	0x4	Unknown
0x1C	0x4	Certainly padding.

Body

The body is encrypted using AES128CBC with key and iv from update_service_sm.self.

Once decrypted:

• 0x100 bytes: a RSA2048 signature, certainly of the PUP
• 0x1E0 bytes: zeroes, maybe area for more than one signature
• 0x100 bytes: RSA2048 signature of the Additional Signature(s)