From PS3Wiki

PUP (Playstation Update Package) files are packages which contain the files used to update a PSP or PS3 system.

The HMAC key used to verify the packages has been released. Look around for "pup-hmac"

Contents 1 Header 1.1 File Table 1.1.1 Filename IDs 1.2 Hash Table 1.3 PS3 Update

Header

Offset	Length	Type	Information
0x0	0x8	unsigned long	Magic
0x8	0x8	unsigned long	Package Version
0x10	0x8	unsigned long	Image Version
0x18	0x8	unsigned long	File Count
0x20	0x8	unsigned long	Header Length
0x28	0x8	unsigned long	File Length
0x30	0x20 * File Count	File Table	File Table
0x30 + (0x20 * File Count)	0x20 * File Count	Hash Table	Hash Table
0x30 + (0x40 * File Count)	0x14	bytes	Header Hash
0x44 + (0x40 * File Count)	0xC	bytes	Unknown

File Table

The file table consists of a number of file entries determined by File Count, with the format below:

Offset	Length	Type	Information
0x0	0x8	unsigned long	Entry ID
0x8	0x8	unsigned long	Data Offset
0x10	0x8	unsigned long	Data Length
0x18	0x8	unsigned long	Unknown

Filename IDs

File Entry ID	Filename
0x100	ps3version.txt
0x101	resource.txt
0x102	shop.txt
0x103	pup_data.txt
0x104	patch_build.txt
0x200	ps3swu.self
0x201	vsh.tar
0x202	dots.txt
0x203	patch_data.pkg
0x300	update_files.tar

Hash Table

The hash table contains a hash entry for every file inside the PUP.

The hash entry format is:

Offset	Length	Type	Information
0x0	0x8	unsigned long	File Entry ID
0x8	0x14	bytes	HMAC-SHA1 hash
0x1C	0x4	unsigned int	Unknown

PS3 Update

DEV NOTE: Information not completely finalized.

Upon PS3 OFW update (.PUP package) the PS3 extracts data to a folder called PS3UPDATE, it then moves that data to /dev_hdd1/ and restarts to install.

Interestingly, the size of the PUP it adds is 5,222KB, which is the same size of a service JIG file, does the lv2diag just copy to /dev_hdd1/ ?

Regardless, I have yet to decrypt a lv2 SELF, I will add here when I do. Until I do, here is a badly done directory structure:

-PS3UPDATE

|-----------a

|-----------ps3swu.self

|-----------PS3UPDAT.PUP

|-----------pup_data.txt

|-----------sys_audio.self

|-data

|-------------Fonts for all languages