Ernie

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Ernie is the codename for the Syscon chip. The Syscon is for exemple responsible for handling button input (including power button), reading/writing to non-volatile storage (NVS) for storing system flags (mostly encrypted and signed). For example IDU flag is stored in NVS. Syscon is also responsible for maintaining the physical address to the resume buffer during Suspend. Communication between Kermit and Syscon is mainly through SPI (see SceSyscon) but there are also some GPIO pins connecting the two. The chip model is NEC/Renesas uPD79F0109 and is likely custom designed for Sony.

Boot Process

The following is logged from boot. The timestamp is in seconds (the starting time is irrelevant). The arrow at the start indicates direction: '>' means Kermit to Syscon (MOSI) and '<' means Syscon to Kermit (MISO). Then there is a 2 byte command id or response code, followed by a flag byte (response only), the payload, a checksum byte, and an (response only) unknown byte. Please note that the packets are listed in transfer order but this may not represent the logical order of the packets. It is currently unknown what the logical order should be, but one can guess that a response is "close to" a request.

First some version information seems to be sent from Syscon to Kermit. This is same for cold boot and resume boot. The last response indicates the type of boot where 0xFF80 is resume and 0xFF14 is regular boot. 

< [2.048118000000000] 0x0004, flags=00, payload=[0D 06 00 01 | ....], chk=0xE1, unk=0x00
> [2.048118000000000] 0x0001, payload=[ | ], chk=0xFD
< [2.048659583333333] 0x0004, flags=00, payload=[00 60 40 00 | .`@.], chk=0x55, unk=0x00
> [2.048659583333333] 0x0005, payload=[ | ], chk=0xF9
< [2.049330083333333] 0x0004, flags=00, payload=[32 30 31 32 31 31 30 38 31 37 30 34 | 201211081704], chk=0x92, unk=0x00
> [2.049330083333333] 0x0002, payload=[ | ], chk=0xFC
< [2.054004333333333] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x30
> [2.054004333333333] 0x0080, payload=[12 00 | ..], chk=0x6A
< [2.058172916666666] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x30
> [2.058172916666666] 0x0000, payload=[ | ], chk=0xFE
< [2.062716333333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x30
> [2.062716333333333] 0x0080, payload=[12 00 | ..], chk=0x6A
< [2.111457750000000] 0x0004, flags=00, payload=[14 FF | ..], chk=0xE4, unk=0x32

Next some encrypted session is established. A 8 byte nonce is sent from Syscon (it appears random for each boot, cold or warm). Encrypted data from this point on always differs each boot. 

> [2.111457750000000] 0x0010, payload=[ | ], chk=0xEE
< [2.133389000000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0xFF
> [2.133389000000000] 0x00A0, payload=[30 00 00 0B 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.......................................], chk=0xFB
< [2.150567250000000] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0xFF
> [2.150567250000000] 0x0000, payload=[ | ], chk=0xFE
< [2.155149500000000] 0x0024, flags=00, payload=[30 01 00 0B 00 00 00 00 A4 B0 EF 23 D6 9A 3A 06 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0..........#..:.........................], chk=0x5F, unk=0x00
> [2.155149500000000] 0x00A0, payload=[30 00 00 0B 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.......................................], chk=0xFB
< [2.163572000000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x01
> [2.163572000000000] 0x00A0, payload=[30 02 00 0B 01 00 00 00 6C 7F E0 79 AA 03 4B B0 96 B7 42 F0 BC F8 62 7A 35 27 53 68 3D 0D ED A7 13 F2 32 77 46 2D 54 F8 | 0.......l..y..K...B...bz5'Sh=.....2wF-T.], chk=0x9B
< [2.189271166666667] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x01
> [2.189271166666667] 0x0000, payload=[ | ], chk=0xFE
< [2.193866583333334] 0x0024, flags=00, payload=[30 03 00 0B 00 00 00 00 7A 44 6E C8 F5 FA 35 CB 9B E9 E6 A0 B6 5C 85 1D FB A8 89 5C 9C 04 0B 29 34 59 55 EB 1D 98 AB 83 | 0.......zDn...5......\.....\...)4YU.....], chk=0xC6, unk=0x00
> [2.193866583333334] 0x00A0, payload=[30 02 00 0B 01 00 00 00 6C 7F E0 79 AA 03 4B B0 96 B7 42 F0 BC F8 62 7A 35 27 53 68 3D 0D ED A7 13 F2 32 77 46 2D 54 F8 | 0.......l..y..K...B...bz5'Sh=.....2wF-T.], chk=0x9B

Some more data is exchanged. Up until this point all the plaintext payloads appear to be the same from coldboot and warmboot. 

< [2.202246333333334] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x03
> [2.202246333333334] 0x088E, payload=[01 22 | ."], chk=0x43
< [2.206411750000000] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x03
> [2.206411750000000] 0x0000, payload=[ | ], chk=0xFE
< [2.217062666666667] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
> [2.217062666666667] 0x0000, payload=[ | ], chk=0xFE
< [2.221620916666667] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
> [2.221620916666667] 0x088E, payload=[01 22 | ."], chk=0x43
< [2.229805500000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x03
> [2.229805500000000] 0x1082, payload=[80 04 08 | ...], chk=0xDD
< [2.233887583333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
> [2.233887583333333] 0x0000, payload=[ | ], chk=0xFE
< [2.238363416666667] 0x0024, flags=00, payload=[FF FF FF FF 01 FF FF FF | ........], chk=0xD7, unk=0x44
> [2.238363416666667] 0x1082, payload=[80 04 08 | ...], chk=0xDD
< [2.246473916666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0xFF

Now, there appears to be a branch. The next sequence only shows up for cold boots. 

> [2.246473916666667] 0x1082, payload=[A0 04 01 | ...], chk=0xC4
< [2.250555000000000] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0xFF
> [2.250555000000000] 0x0000, payload=[ | ], chk=0xFE
< [2.255030833333334] 0x0024, flags=00, payload=[FF | .], chk=0xD9, unk=0x00
> [2.255030833333334] 0x1082, payload=[A0 04 01 | ...], chk=0xC4
< [2.259176583333333] 0x0004, flags=00, payload=[01 01 13 00 | ....], chk=0xE0, unk=0xFF
> [2.259176583333333] 0x1100, payload=[ | ], chk=0xED
< [2.263720583333333] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x01
> [2.263720583333333] 0x00D0, payload=[30 00 00 0F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.......................................], chk=0xC7
< [2.267827000000000] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x01
> [2.267827000000000] 0x0000, payload=[ | ], chk=0xFE
< [2.278339666666667] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x01
> [2.278339666666667] 0x0000, payload=[ | ], chk=0xFE
< [2.282830833333333] 0x0024, flags=00, payload=[30 01 00 0F 00 00 00 00 E1 CA 65 96 BB 7E 81 7A 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.........e..~.z........................], chk=0x97, unk=0x00
> [2.282830833333333] 0x00D0, payload=[30 00 00 0F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.......................................], chk=0xC7
< [2.291023500000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x01
> [2.291023500000000] 0x00D0, payload=[30 02 00 0F 01 00 00 00 4E D7 C0 7C D5 E8 BB D7 3E 9E 43 7B B2 E3 4D 81 23 C8 C4 BF B8 4D 9B 25 0A 3D C7 45 E6 0D 23 43 | 0.......N..|....>.C{..M.#....M.%.=.E..#C], chk=0x38
< [2.295129250000000] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x01
> [2.295129250000000] 0x0000, payload=[ | ], chk=0xFE
< [2.305641750000000] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x01
> [2.305641750000000] 0x0000, payload=[ | ], chk=0xFE
< [2.310132916666667] 0x0024, flags=00, payload=[30 03 00 0F 00 00 00 00 5B 3E 5C 5F 11 F9 E4 6A 85 0D 1E 06 9E F9 33 25 9B 95 55 21 39 48 FC 55 C7 BF A7 E4 32 AD FC 65 | 0.......[>\_...j......3%..U!9H.U....2..e], chk=0x55, unk=0x00
> [2.310132916666667] 0x00D0, payload=[30 02 00 0F 01 00 00 00 4E D7 C0 7C D5 E8 BB D7 3E 9E 43 7B B2 E3 4D 81 23 C8 C4 BF B8 4D 9B 25 0A 3D C7 45 E6 0D 23 43 | 0.......N..|....>.C{..M.#....M.%.=.E..#C], chk=0x38
< [2.318358166666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x03
> [2.318358166666667] 0x00D0, payload=[30 04 00 0F 00 00 00 00 52 8D 6D BC 90 C9 00 EE FA CA 47 63 10 D1 4A E5 5A FD BB 91 3A 6C DA EF 64 CA 71 01 4A A9 D5 31 | 0.......R.m.......Gc..J.Z...:l..d.q.J..1], chk=0x4B
< [2.322464250000000] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x03
> [2.322464250000000] 0x0000, payload=[ | ], chk=0xFE
< [2.332976833333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
> [2.332976833333333] 0x0000, payload=[ | ], chk=0xFE
< [2.337468000000000] 0x0024, flags=00, payload=[30 05 00 0F 00 00 00 00 52 8D 6D BC 90 C9 00 EE FA CA 47 63 10 D1 4A E5 5A FD BB 91 3A 6C DA EF 64 CA 71 01 4A A9 D5 31 | 0.......R.m.......Gc..J.Z...:l..d.q.J..1], chk=0xF5, unk=0x00
> [2.337468000000000] 0x00D0, payload=[30 04 00 0F 00 00 00 00 52 8D 6D BC 90 C9 00 EE FA CA 47 63 10 D1 4A E5 5A FD BB 91 3A 6C DA EF 64 CA 71 01 4A A9 D5 31 | 0.......R.m.......Gc..J.Z...:l..d.q.J..1], chk=0x4B
< [2.345696333333333] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x05

Then another set of shared sequence. Some differences in the warmboot responses though. On line 18, 

FF BF FF 74

becomes 

FF FF FF 74

. On line 12, the 

00 00 00 00

becomes the address of the resume buffer (ex 

F0 1E 1F 41

). 

> [2.345696333333333] 0x00D2, payload=[20 7A 3E 7B 31 DE FC 3A 11 5F 64 E7 AB A4 EC 17 | .z>{1..:._d.....], chk=0x77
< [2.349790333333333] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x05
> [2.349790333333333] 0x0000, payload=[ | ], chk=0xFE
< [2.360448916666666] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x05
> [2.360448916666666] 0x0000, payload=[ | ], chk=0xFE
< [2.364930250000000] 0x0024, flags=00, payload=[9D 0B BC 4D BA 66 40 2C 63 BE F3 79 D0 31 26 1E 47 3A 64 DE 68 2F AE E2 8A B6 F0 27 37 46 89 16 0E 71 04 FA BF C9 4A A1 DF 4B EF D3 3D 0D 39 CD | ...M.f@,c..y.1&.G:d.h/.....'7F...q....J..K..=.9.], chk=0x11, unk=0x00
> [2.364930250000000] 0x00D2, payload=[20 7A 3E 7B 31 DE FC 3A 11 5F 64 E7 AB A4 EC 17 | .z>{1..:._d.....], chk=0x77
< [2.373236666666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x0B
> [2.373236666666667] 0x0090, payload=[0C 00 04 | ...], chk=0x5B
< [2.377318583333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x0B
> [2.377318583333333] 0x0000, payload=[ | ], chk=0xFE
< [2.381794416666667] 0x0024, flags=00, payload=[00 00 00 00 | ....], chk=0xD5, unk=0x66
> [2.381794416666667] 0x0090, payload=[0C 00 04 | ...], chk=0x5B
< [2.385879750000000] 0x0004, flags=00, payload=[40 00 | @.], chk=0xB7, unk=0x00
> [2.385879750000000] 0x0800, payload=[ | ], chk=0xF6
< [2.386382583333333] 0x0004, flags=00, payload=[FF BF FF 74 | ...t], chk=0xC4, unk=0x66
> [2.386382583333333] 0x0100, payload=[ | ], chk=0xFD
< [2.386871833333333] 0x0004, flags=00, payload=[10 00 00 00 | ....], chk=0xE5, unk=0x66
> [2.386871833333333] 0x0003, payload=[ | ], chk=0xFB
< [2.387380083333333] 0x0000, flags=3F, payload=[ | ], chk=0xBE, unk=0x00
> [2.387380083333333] 0x0006, payload=[ | ], chk=0xF8
< [2.481997666666667] 0x0000, flags=80, payload=[ | ], chk=0x7D, unk=0x00
> [2.481986333333333] 0x00D2, payload=[30 14 F4 B8 84 89 81 AB 3D 07 66 DE AE B6 D3 24 | 0.......=.f....$], chk=0x10
< [2.514678500000000] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0x00
> [2.514678500000000] 0x0000, payload=[ | ], chk=0xFE
< [2.519163916666667] 0x0020, flags=00, payload=[1A 1F BC 74 AA 16 59 D6 5C E7 FF 5B E0 85 B2 C8 39 2D D6 95 98 2F B7 4B 71 64 34 D7 8D 2C 94 A1 91 CB 73 D7 8D E1 D0 07 E6 1E 0F DA E7 51 BC 69 | ...t..Y.\..[....9-.../.Kqd4..,....s..........Q.i], chk=0x3C, unk=0x00
> [2.519163916666667] 0x00D2, payload=[30 14 F4 B8 84 89 81 AB 3D 07 66 DE AE B6 D3 24 | 0.......=.f....$], chk=0x10
< [2.527551416666667] 0x0000, flags=80, payload=[ | ], chk=0x7D, unk=0x1F
> [2.527540083333333] 0x088E, payload=[02 29 | .)], chk=0x3B
< [2.531619416666667] 0x0000, flags=00, payload=[ | ], chk=0xFD, unk=0x1F
> [2.531619416666667] 0x0000, payload=[ | ], chk=0xFE
< [2.542392416666666] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0x1F
> [2.542392416666666] 0x0000, payload=[ | ], chk=0xFE
< [2.546867583333333] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0x1F
> [2.546867583333333] 0x088E, payload=[02 29 | .)], chk=0x3B

Then, the two boot paths diverge completely (also note the time jump). It is suspected that at this point the kernel is started up on coldboot, and the kernel resumes for warmboot. For cold boot only, we see the beginning init sequence again, which is likely done in SceSyscon. 

< [3.322105750000000] 0x0000, flags=00, payload=[0D 06 00 01 | ....], chk=0xE5, unk=0x16
> [3.322105750000000] 0x0001, payload=[ | ], chk=0xFD
< [3.326563916666667] 0x0000, flags=00, payload=[32 30 31 32 31 31 30 38 31 37 30 34 | 201211081704], chk=0x96, unk=0x85
> [3.326552583333333] 0x0002, payload=[ | ], chk=0xFC
< [3.331090666666667] 0x0000, flags=80, payload=[ | ], chk=0x7D, unk=0x30
> [3.331079333333333] 0x0080, payload=[12 00 | ..], chk=0x6A
< [3.331576333333333] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0x30
> [3.331576333333333] 0x0080, payload=[12 00 | ..], chk=0x6A
< [3.332068833333333] 0x0000, flags=00, payload=[10 00 00 00 | ....], chk=0xE9, unk=0x31
> [3.332068833333333] 0x0004, payload=[ | ], chk=0xFA
< [3.332541666666667] 0x0000, flags=00, payload=[00 FF 04 00 | ....], chk=0xF6, unk=0x31
> [3.332541666666667] 0x0103, payload=[ | ], chk=0xFA
< [3.336980333333333] 0x0000, flags=00, payload=[10 00 00 00 | ....], chk=0xE9, unk=0x31
> [3.336980333333333] 0x0003, payload=[ | ], chk=0xFB
...

Packet checksum

The checksum byte of the packet is calculated as the binary negation of the sum of the packet (including the 2 bytes of the command id and the byte for the length). The checksum calculation can be implemented as follows: 

void syscon_calc_checksum(unsigned char packet[32], int length)
{
	int i;
	unsigned char hash = 0;
	
	for (i = 0; i < 3 + length; i++)
		hash += packet[i];

	packet[3 + length] = ~hash;
}

Commands

Commands are listed in the order seen in cold boot. The numbers in the captured packets indicate the assumed order with some unused packets filtered out (they appear to be resent). The ordering and grouping are assumed and may contain errors.

CMD 0x0001

Gets some device specific version. Maybe chipset revision? Can also be seen in the packet header in Syscon Update. Also sent at kernel boot. 

SEND 1    > [2.881037083333333] 0x0001, payload=[ | ], chk=0xFD
RESP 1    < [2.881037083333333] 0x0004, flags=00, payload=[0D 06 00 01 | ....], chk=0xE1, unk=0x71

SEND 23   > [4.167151583333333] 0x0001, payload=[ | ], chk=0xFD
RESP 23   < [4.167151583333333] 0x0000, flags=00, payload=[0D 06 00 01 | ....], chk=0xE5, unk=0x32

CMD 0x0005 - Get Hardware Configuration

Gets Hardware Configuration. Can be obtained using sceSysconGetHardwareInfoForDriver or sceSysconGetHardwareInfo2ForDriver.
Can also be seen in the packet header in Syscon Update. 

SEND 2    > [2.881578833333333] 0x0005, payload=[ | ], chk=0xF9
RESP 2    < [2.881578833333333] 0x0004, flags=00, payload=[00 60 40 00 | .`@.], chk=0x55, unk=0x71

CMD 0x0002

Gets syscon version string. Likely refers to hardware version. Also sent at kernel boot. 

SEND 3    > [2.882249083333333] 0x0002, payload=[ | ], chk=0xFC
RESP 3    < [2.882249083333333] 0x0004, flags=00, payload=[32 30 31 32 31 31 30 38 31 37 30 34 | 201211081704], chk=0x92, unk=0x00

SEND 24   > [4.171598000000000] 0x0002, payload=[ | ], chk=0xFC
RESP 24   < [4.171598000000000] 0x0000, flags=00, payload=[32 30 31 32 31 31 30 38 31 37 30 34 | 201211081704], chk=0x96, unk=0xF7

CMD 0x0080

Unknown. Sends data 0x0012 on 3.60. Does not get return data. Also sent at kernel boot. 

SEND 4    > [2.895635416666666] 0x0080, payload=[12 00 | ..], chk=0x6A
RESP 4    < [2.886923416666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x30
RESP 4    < [2.891092083333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x30
RESP 4    < [2.895635416666666] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x30

SEND 25   > [4.176620750000000] 0x0080, payload=[12 00 | ..], chk=0x6A
RESP 25   < [4.176123750000000] 0x0000, flags=80, payload=[ | ], chk=0x7D, unk=0x30
RESP 25   < [4.176620750000000] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0x30

CMD 0x0010

Boot type indicator. 0xFF14 on cold boot. 0xFF80 on resume boot. 

SEND 5    > [2.950546416666667] 0x0010, payload=[ | ], chk=0xEE
RESP 5    < [2.950546416666667] 0x0004, flags=00, payload=[14 FF | ..], chk=0xE4, unk=0x32

CMD 0x00A0

Runs twice. Appears to contain a 8 byte inner header. First packet sends all zeros and gets back a 8 byte random response. This is likely a nonce or challenge. This likely establishes an encrypted session. Encrypted data differs on each boot. There does not appear to be data transferred using the established session. 

SEND 6    > [2.994470666666667] 0x00A0, payload=[30 00 00 0B 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.......................................], chk=0xFB
RESP 6    < [2.972471333333333] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0xFF
RESP 6    < [2.989889500000000] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0xFF
RESP 6    < [2.994470666666667] 0x0024, flags=00, payload=[30 01 00 0B 00 00 00 00 CA 71 11 BA 86 87 EF 0D 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0........q..............................], chk=0x66, unk=0x00

SEND 7    > [3.033187750000000] 0x00A0, payload=[30 02 00 0B 01 00 00 00 92 45 B4 A5 49 15 CE F2 39 0E 9E 4C BF FA 19 E6 5D CF BA 5A 6E C3 7C ED 2A 6D 4E 79 84 28 1C 2A | 0........E..I...9..L....]..Zn.|.*mNy.(.*], chk=0x97
RESP 7    < [3.002893083333333] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x01
RESP 7    < [3.028592333333334] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x01
RESP 7    < [3.033187750000000] 0x0024, flags=00, payload=[30 03 00 0B 00 00 00 00 12 77 A5 98 67 F7 38 9B B4 54 48 FE 84 82 CF 84 41 42 87 A2 EA D1 CF 9C 5B D1 2A 3F 1E 50 B9 3D | 0........w..g.8..TH.....AB......[.*?.P.=], chk=0x0A, unk=0x00

CMD 0x088E

Unknown. Sends data 0x2201 on 3.60 and does not get a response. 

SEND 8    > [3.061354583333333] 0x088E, payload=[01 22 | ."], chk=0x43
RESP 8    < [3.041713500000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x03
RESP 8    < [3.046148250000000] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x03
RESP 8    < [3.056796250000000] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
RESP 8    < [3.061354583333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03

CMD 0x1082

Unknown. Seems to get data from NVS? Looks like 2-byte index/offset followed by 1 byte length. Could be used to fetch boot-time flags or something. 

SEND 9    > [3.078212500000000] 0x1082, payload=[80 04 08 | ...], chk=0xDD
RESP 9    < [3.069790250000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x03
RESP 9    < [3.073736583333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
RESP 9    < [3.078212500000000] 0x0024, flags=00, payload=[FF FF FF FF 01 FF FF FF | ........], chk=0xD7, unk=0x77

SEND 10   > [3.094879833333333] 0x1082, payload=[A0 04 01 | ...], chk=0xC4
RESP 10   < [3.086322916666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0xFF
RESP 10   < [3.090404000000000] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0xFF
RESP 10   < [3.094879833333333] 0x0024, flags=00, payload=[FF | .], chk=0xD9, unk=0x00

CMD 0x1100

Unknown. Could be syscon firmware version. 

SEND 11   > [3.099025500000000] 0x1100, payload=[ | ], chk=0xED
RESP 11   < [3.099025500000000] 0x0004, flags=00, payload=[01 01 13 00 | ....], chk=0xE0, unk=0xFF

CMD 0x00D0

Some encrypted transfer that looks close to Syscon#CMD 0x00A0 in format. Different on each boot. 

SEND 12   > [3.122679833333333] 0x00D0, payload=[30 00 00 0F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.......................................], chk=0xC7
RESP 12   < [3.103569583333333] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x01
RESP 12   < [3.107676166666667] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x01
RESP 12   < [3.118188666666667] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x01
RESP 12   < [3.122679833333333] 0x0024, flags=00, payload=[30 01 00 0F 00 00 00 00 9F CC 4A 69 73 E9 C0 5A 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0.........Jis..Z........................], chk=0xDD, unk=0x00

SEND 13   > [3.150031916666667] 0x00D0, payload=[30 02 00 0F 01 00 00 00 98 6D 3A 1E C5 B1 E9 AF 54 65 55 91 3B DF 2B A8 0F AD B0 73 A0 A2 0F EE 5D 0A AF 41 A5 6D 32 20 | 0........m:.....TeU.;.+....s....]..A.m2.], chk=0xF4
RESP 13   < [3.130872500000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x01
RESP 13   < [3.134978166666667] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x01
RESP 13   < [3.145539833333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x01
RESP 13   < [3.150031916666667] 0x0024, flags=00, payload=[30 03 00 0F 00 00 00 00 F5 19 C0 67 09 80 C6 DB 58 8D FB E1 86 22 D1 00 DA BB D2 AF AA 51 F9 57 7C 56 92 0A 94 D6 60 4D | 0..........g....X....".......Q.W|V....`M], chk=0xF0, unk=0x00

SEND 14   > [3.177452416666667] 0x00D0, payload=[30 04 00 0F 00 00 00 00 87 4E 59 41 22 98 F8 62 BD B4 C8 4F 4C 0A 81 90 47 1E 1E 70 D6 51 57 42 E5 EC 07 A2 D4 CF E5 02 | 0........NYA"..b...OL...G..p.QWB........], chk=0x9A
RESP 14   < [3.158257166666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x03
RESP 14   < [3.162363250000000] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x03
RESP 14   < [3.172875666666667] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x03
RESP 14   < [3.177452416666667] 0x0024, flags=00, payload=[30 05 00 0F 00 00 00 00 87 4E 59 41 22 98 F8 62 BD B4 C8 4F 4C 0A 81 90 47 1E 1E 70 D6 51 57 42 E5 EC 07 A2 D4 CF E5 02 | 0........NYA"..b...OL...G..p.QWB........], chk=0x44, unk=0x00

CMD 0x00D2

This command is used twice during boot and also quite often after boot. Data is different on each boot. Encrypted session using key from handshake above. Second transaction seems to be the firmware version data written during the update process. Likely firmware version check is done here. 

SEND 15   > [3.204733083333333] 0x00D2, payload=[32 78 88 CF 3E 63 56 19 75 3A 0A 2D F3 49 63 E2 | 2x..>cV.u:.-.Ic.], chk=0xA4
RESP 15   < [3.185595250000000] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x05
RESP 15   < [3.189740333333333] 0x0004, flags=00, payload=[ | ], chk=0xF9, unk=0x05
RESP 15   < [3.200251666666666] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x05
RESP 15   < [3.204733083333333] 0x0024, flags=00, payload=[D3 57 9B F2 A2 45 E2 7A 2A FC 84 12 97 8E 23 5F C8 AB FB 58 97 EC DE 20 94 0A 78 28 C6 EE C5 45 18 29 00 F4 56 22 53 AF 24 47 8E FF B1 5C DA 2F | .W...E.z*.....#_...X......x(...E.)..V"S.$G...\./], chk=0x4C, unk=0xFF

SEND 21   > [3.359112250000000] 0x00D2, payload=[1C 0B 9E FF FB 68 90 4B FD C2 05 CD D8 67 4D D0 | .....h.K.....gM.], chk=0x2D
RESP 21   < [3.321934500000000] 0x0000, flags=80, payload=[ | ], chk=0x7D, unk=0x00
RESP 21   < [3.354626666666667] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0x00
RESP 21   < [3.359112250000000] 0x0020, flags=00, payload=[6C B4 26 F3 CD 32 D3 3E 6F 80 F2 0F 68 F7 E2 96 58 DB 2F BB AB A6 98 DD 26 14 DD 61 12 E4 55 BA BB 32 1D 1F 75 D5 D1 4C 7E 4A 19 42 E5 B0 C6 AB | l.&..2.>o...h...X./.....&..a..U..2..u..L~J.B....], chk=0x84, unk=0xFF

CMD 0x0090

This fetches the saved resume buffer paddr. Kernel sets this before suspending and this value is passed to the resume function. See Suspend. The format is 2 byte index and 1 byte length. There are likely other data stored at other indexes. 

SEND 16   > [3.221743166666667] 0x0090, payload=[0C 00 04 | ...], chk=0x5B
RESP 16   < [3.213273166666667] 0x0004, flags=80, payload=[ | ], chk=0x79, unk=0x57
RESP 16   < [3.217267333333333] 0x0024, flags=00, payload=[ | ], chk=0xD9, unk=0x57
RESP 16   < [3.221743166666667] 0x0024, flags=00, payload=[F0 0E 1F 41 | ...A], chk=0x77, unk=0x45

CMD 0x0800

Unknown. 

SEND 17   > [3.225828583333334] 0x0800, payload=[ | ], chk=0xF6
RESP 17   < [3.225828583333334] 0x0004, flags=00, payload=[40 00 | @.], chk=0xB7, unk=0x41

CMD 0x0100

Unknown. Likely related to indicating if this is a cold or warm boot. On warm boot, the data returned is FF FF FF 74. 

SEND 18   > [3.226331500000000] 0x0100, payload=[ | ], chk=0xFD
RESP 18   < [3.226331500000000] 0x0004, flags=00, payload=[FF BF FF 74 | ...t], chk=0xC4, unk=0x45

CMD 0x0003

Unknown. 

SEND 19   > [3.226820750000000] 0x0003, payload=[ | ], chk=0xFB
RESP 19   < [3.226820750000000] 0x0004, flags=00, payload=[10 00 00 00 | ....], chk=0xE5, unk=0x45

CMD 0x0006

Unknown. 

SEND 20   > [3.227328833333333] 0x0006, payload=[ | ], chk=0xF8
RESP 20   < [3.227328833333333] 0x0000, flags=3F, payload=[ | ], chk=0xBE, unk=0x00

CMD 0x088E

Unknown. Appears to be the last command sent before a time-jump (likely indicating completion of early-boot). Might be some status indicator to tell Syscon that we're done. 

SEND 22   > [3.386554833333333] 0x088E, payload=[02 29 | .)], chk=0x3B
RESP 22   < [3.367488416666667] 0x0000, flags=80, payload=[ | ], chk=0x7D, unk=0xB4
RESP 22   < [3.371567833333333] 0x0000, flags=00, payload=[ | ], chk=0xFD, unk=0xB4
RESP 22   < [3.382079833333334] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0xB4
RESP 22   < [3.386554833333333] 0x0020, flags=00, payload=[ | ], chk=0xDD, unk=0xB4

CMD 0x0004

Unknown. Likely happens after initial boot. 

SEND 26   > [4.177113250000000] 0x0004, payload=[ | ], chk=0xFA
RESP 26   < [4.177113250000000] 0x0000, flags=00, payload=[10 00 00 00 | ....], chk=0xE9, unk=0x31

CMD 0x0103

Unknown. Likely happens after initial boot. Might be get Wakeup factor. 

SEND 27   > [4.177586083333333] 0x0103, payload=[ | ], chk=0xFA
RESP 27   < [4.177586083333333] 0x0000, flags=00, payload=[00 FF 04 00 | ....], chk=0xF6, unk=0x31

Pinout

UART

Name Pin Description
CTS0 J7 UART0 clear to send
RTS0 C6 UART0 request to send
TX0 B6 UART0 transmit
RX0 F11 UART0 receive
SW0 A8 Switch, see UART Console#OLED PSVita UART5 location

SPI

Main communication with Kermit.

Name Pin Description
CS A7
MISO A6 UART0 request to send
MOSI C7 UART0 transmit
SCK B7 UART0 receive

Other

Name Pin Description
? C11 UDC pin 11
? F9 UDC pin 12
? G4 UDC pin 13
? G8 SN99057 pin 38
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