Syscon Update

Structure

Ernie updates are stored in a packet format.

Packet Header

Any update packet has a common header structure.

Offset	Size	Description
0x0	0x1	Type (ex: 1, 2, 0x10, 0x20)
0x1	0x1	Header Size (ex: 0x10, 0x18)
0x2	0x2	Size (ex: 0, 0x400, 0x800)

Packet size varies depending on the hardware revision of Syscon:

Renesas 78K0R/Kx3: 0x800
Renesas 78K0R/Kx3-L: 0x400
Renesas RL78/G13: 0x400

Packet Types

0x01

Version packet.

This packet is update header field.

Offset	Size	Description
0x0	0x4	Packet Header
0x4	0x4	Firmware Version. Version of the Ernie software update. (ex: 0x0100060B -> 1.0.6.11)
0x8	0x4	Hardware Info. PSVita hardware on which this update can be installed. (ex: 0x00723030)
0xC	0x4	Padding

Ernie Version and Hardware Info from a few PUPs:

1.80 CEX
0B 06 00 01 00 32 60 00
0B 06 00 01 00 30 60 00
0B 06 00 01 00 20 60 00
0B 06 00 01 00 10 60 00
0B 06 00 01 00 60 40 00

1.81 CEX
0B 06 00 01 00 32 60 00
0B 06 00 01 00 30 60 00
0B 06 00 01 00 20 60 00
0B 06 00 01 00 10 60 00
0B 06 00 01 00 60 40 00

3.15 CEX
11 05 03 01 38 50 80 00
03 06 03 01 30 30 70 00
0D 06 00 01 00 32 60 00
0D 06 00 01 00 30 60 00
0D 06 00 01 00 20 60 00
0B 06 00 01 00 10 60 00
0D 06 00 01 00 60 40 00

3.30 CEX
11 05 03 01 38 50 80 00
01 03 04 01 30 30 72 00
03 06 03 01 30 30 70 00
0D 06 00 01 00 32 60 00
0D 06 00 01 00 30 60 00
0D 06 00 01 00 20 60 00
0B 06 00 01 00 10 60 00
0D 06 00 01 00 60 40 00

1.69 TOOL
06 03 00 01 00 40 41 00
06 03 00 01 00 50 41 00
03 02 09 00 00 50 31 00
06 03 00 01 00 10 41 00
06 03 00 01 00 52 41 00
06 03 00 01 03 26 10 00
06 03 00 01 00 52 31 00

1.80 TOOL
0B 06 00 01 00 10 60 00
0B 06 00 01 00 60 41 00
0B 06 00 01 00 52 41 00
06 03 00 01 03 26 10 00

0x02

Key revision packet.

This packet embeds the encryption key revision used to decrypt the Syscon update packets.

Offset	Size	Description
0x0	0x4	Packet Header
0x4	0x4	Image Size (ex: 0)
0x8	0x4	Firmware Type (ex: 0, 1, 2)
0xC	0x4	Padding

• Firmware Type 0 is for Renesas 78K0R Proto. It is supported since at least FW 0.931 (FW 0.902 doesn't support it) until FW 1.692. It is for Fat PSVita prototype.
• Firmware Type 1 is for Renesas 78K0R. It is supported since about FW 1.00. It is for most Fat PSVitas and for PSTV.
• Firmware Type 2 is for Renesas RL78. It is supported since FW 2.50. It is for PSVita Slim Syscon.

0x03

This packet is special because it is not embedded in Syscon Update SPKGs. It is generated in ARM kernel and sent to Syscon with Syscon command 0x1185.

It is not present on FW 0.931.

Offset	Size	Description
0x0	0x4	Packet Header
0x4	0x18	Unknown data
0x1C	0x4	Padding

0x10

Encrypted segment packet.

Segments are concatenated before being AES128CBC encrypted/decrypted.

Offset	Size	Description
0x0	0x4	Packet Header
0x4	0x4	Segment Number. Must be between 0 and 0x17F.
0x8	0x4	Size (ex: 0x400 for Renesas RL78/G13 and NEC 78K0R/Kx3, 0x800 for NEC 78K0R/Kx3-L)
0xC	0x4	Padding
0x10	Variable	Encrypted data

0x20

Hash packet.

Offset	Size	Description
0x0	0x4	Packet Header
0x4	0x14	Hash. Sha-1 hash of decrypted concatenated segments.

Ernie Update steps

• ARM PSVita updater arrives at last step: Ernie update.
• ARM PSVita updater decrypts Ernie update SPKGs til it finds one whose Hardware Info matches.
• ARM PSVita updater sends the encrypted segments directly to Ernie using some command 0x1181.
• ARM PSVita updater sends the hash directly to Ernie using some command 0x1184.
• Ernie decrypts concatenated received segments using AES128CBC.
• Ernie computes sha1 over the decrypted concatenated data and compares with the received hash.
• Ernie installs the update using the decrypted data.