MechaCon

MechaCon is short for Mechanics Controller. Its main function of it is to control the drive mechanism. However, this chip is also the security ic of the PlayStation 2 that implements game disk security, Magic Gate and KELF file decryption.

There are two known main variants of it.

The earlier one is based on the 16-bit SPC970 CPU core and was used till GH-022. Chip name starts with "CXP10". Older versions come in a 100-pin QFP package, newer versions in a 136-ball BGA package.

The newer one is ARM-based, codenamed "Dragon", and used from GH-023 (SCPH-5000X) onwards. Chip name starts with "CXR7". All versions come in a 164-ball BGA package. Besides this, "Dragon" also includes the functions that were fulfilled by the separate SysCon chip on earlier boards up to GH-022, as well as the RTC+EEPROM chip, which was separate on earlier boards (or dedicated EEPROM and RTC chips on even earlier boards).

Both have access to a 1 KB / 512 words EEPROM. The EEPROM content is different between the SPC970-based MechaCon and Dragon.

For the SPC970 MechaCon, the EEPROM is an external chip; either a dedicated EEPROM chip on older boards or a combined Rohm RTC+EEPROM chip on later boards.
Dragon has the die of the combined Rohm RTC+EEPROM chip inside its own chip package, however, the EEPROM pins are exposed on the package, and the connection between Dragon and the RTC+EEPROM is done externally on the motherboard.

Every MechaCon has a 3.3 V TTL UART interface that was used by service centers for example to readjust the drive and write calibration data etc. Today it can be used with tools like PMAP (currently supports consoles up to I-chassis) to readjust the drive mechanism after fitting a replacement laser assembly etc.

SPC970

Hardware revisions

• CXP101064 (only used on early A-chassis/GH-001 boards)
• CXP102064 (used from later A-chassis to D/D'-chassis boards)
• CXP103049 (BGA case, used in F and G-chassis)

The CXP103049 requires a working battery to function properly.

Firmware revisions

Firmware comes in an OTP or mask ROM inside MechaCon.

TODO

Dragon

Hardware revisions

• CXR706F080 (has a flash ROM for firmware; used for engineering, not used in retail consoles)
• CXR706080 (used in H, I and J chassis SCPH-5XXXX consoles as well as in PSX)
• CXR716080 (used in K, L and M slim chassis SCPH-70XXX, SCPH-75XXX and SCPH-77XXX consoles)
• CXR726080 (used in N, P and R slim chassis SCPH-79XXX and SCPH-9XXXX consoles)

Firmware revisions

Firmware comes in an OTP or mask ROM inside MechaCon, except in CXR706F080, which has a reprogrammable flash ROM. It is however possible to apply patches to it via EEPROM.

Dumps: https://mega.nz/folder/MNpAQDzJ#bZpyfb7aGrhGDMR_ZGA8ig

Early versions of the Dragon MechaCon firmware (specifically in SCPH-5XXXX and SCPH-70XXX consoles) have a tendency to crash by sheer bad luck or on badly readable discs (e.g. badly burned/low-quality DVD-R discs or scratched originals), overvolting the focus/tracking coils of the laser and killing them and also the driver IC in the process. Several hardware-based mitigations/"fixes" have been developed by the community to address this issue with varying degrees of success. The most notable of these fixes are the "Romeo-mod"/"LA-fix" for SCPH-5XXXX consoles and "summ0ne's fix" for SCPH-70XXX consoles.

EEPROM layout

Start (word)	End (word)	Size (byte)	Offset in file	Description
0	48	0x60	0x0
48	90	0x54	0x60
90	96	0xC	0xB4	gap
96	128	0x40	0xC0
128	150	0x2C	0x100
150	160	0x14	0x12C	gap
160	190	0x3C	0x140
190	192	0x4	0x17C	gap
192	198	0xC	0x180	Region params (only slim)
198	204	0xC	0x18C	gap
204	208	0x8	0x198	MAC address (only slim)
208	211	0x6	0x1A0	gap
211	216	0xA	0x1A6	wake up time
216	225	0x12	0x1B0	model number
225	227	0x4	0x1C2	gap
227	232	0xA	0x1C6	Region code key seed
232	237	0xA	0x1D0	Region code ciphertext
237	240	0x6	0x1DA	gap
240	245	0xA	0x1E0	iLink id
245	248	0x6	0x1EA	(used by scmd 3, subcmd 48 and 49)
248	253	0xA	0x1F0	Console id
253	256	0x6	0x1FA	(used by scmd 3, subcmd 48 and 49)
256	312	0x70	0x200	config 2
312	344	0x40	0x270	config 0
344	400	0x70	0x2B0	config 1
400	512	0xE0	0x320	Rom patches ciphertext

Region params

Offset		Size	Description
0x180		0x0C	Various region parameters. Type char. Zero padded. On dragon FATs (mechacon v5) filled with FF. Does not have checksum. Normally write-protected by mechacon.
1	0x180	1	On 70k exists but has no effect. On Deckard will patch rom0:ROMVER (4th byte 0220HD20060905) and rom0. Possible values: "J" - for Japan, "A" - for America and Mexico, "E" - for Europe, Oceania and Russia, "H" - for region Asia, Taiwan, Korea, "C" - for region Mainland China. Each region checks license data in the PS2 titles. A region has this check disabled. H region untested.
	0x181	4	On all slims will patch rom0:OSDVER (5-8th byte) ("0190Csch"). This mostly controls OSD language sets, and other changes are not tested. Possible values: "Jjpn" - for Japan, "Aeng" - for America, "Eeng" - for Europe and Oceania, "Heng" - for Asia, "Reng" - for Russia, "Csch" - for mainland China, "Kkor" - for Korea, "Htch" - for Taiwan, "Aspa" - for Mexico. "Ccsh" will crash cause rom2 (containing Simplified Chinese font) is missing on slims.
	0x185	1	On 70k exists but has no effect. On Deckard will patch rom0:VERSTR (0x22 byte: "System ROM Version 5.0 06/23/03 J") and rom0. Possible values: "J" - for Japan, Asia, Taiwan, Korea, China, "A" - for America, Mexico, "E" - for Europe, Oceania and Russia. Each region checks license data in the PS1 titles. A region has this check disabled.
	0x185	1	On all slims will patch rom1:DVDID (5th byte) ("3.11A"). This change DVD player region. Possible values: "JUEAORCM".

Region code

Decryption

int getRegionFlags()
{
	// read kek
	uint8_t key508[8];
	ksGetKey(key508, 508);
	
	// read saved seed from eeprom
	uint8_t keyseed[10];
	eepromRead(227, sizeof(keyseed), keyseed);
	
	// read encrypted region from eeprom
	uint8_t ciphertext[10];
	eepromRead(232, sizeof(ciphertext), ciphertext);
	
	// generate key
	uint8_t key[8];
	desEncrypt(key508, keyseed, key);
	
	// decrypt ciphertext
	uint8_t plaintext[8];
	desDecrypt(key, ciphertext, plaintext);
	
	uint16_t crc = *(uint16_t *) plaintext;
	crc += *(uint16_t *) &plaintext[2];
	crc += *(uint16_t *) &plaintext[4];
	
	// check checksum
	if (crc  == *(uint16_t *) &plaintext[6])
		return *(uint32_t *) plaintext;
	
	retrun 0;
}

Bits

Bit	Description
0	Japan
1	USA
2	Europe
3	Oceania
4	Asia
5	Russia
6	China
7	Mexico
16	Development (changes MagicGate keys)
17	Retail MagicGate keys on Development, bypass BootCertify
18	Arcade (changes MagicGate keys)
19	Prototype? (changes MagicGate keys)
20	? (dvd related)

Rom patch

Decryption

bool readAndDecryptRomPatch()
{
	// read the patch's first half
	uint8_t patches[0xDE];
	eepromRead(400, 0x70, patches);
	
	// check if the -1th byte is 0 (sum is not checked)
	if (patches[0x6E])
		return false;

	// read the patch's second half
	eepromRead(456, 0x70, &patches[0x6E]);
	
	// check if the -1th byte is 0 (sum is not checked)
	if (patches[0xDC])
		return false;

	// read encryption key
	uint8_t key504[8];
	ksGetKey(key504, 504);
	
	// decrypt the patch using DES-ECB
	for (int i = 0; i < 0xD8; i += 8)
		desDecrypt(key504, &patches[i], &patches[i]);

	// check sum
	uint32_t sum = *(uint32_t *)patches;
	sum += *(uint32_t *)&patches[4];
	sum += *(uint32_t *)&patches[8];
	sum += *(uint32_t *)&patches[12];

	if (*(uint32_t *) &patches[0xD8] == ~sum)
		return false;
		
	return true;
}

Content

The patch can contain up to 4 patches.

addressX = The address where to apply the patch

valueX = The data that's written there

svc_addressX = The address where SVC X instruction jumps to.

payload = Arbitrary, could be code or data as well.

Offset	Size	Name
0x00	0x04	address0
0x04	0x04	address1
0x08	0x04	address2
0x0C	0x04	address3
0x10	0x04	value0
0x14	0x04	value1
0x18	0x04	value2
0x1C	0x04	value3
0x20	0x04	svc_address0
0x24	0x04	svc_address1
0x28	0x04	svc_address2
0x2C	0x04	svc_address3
0x30	0xA8	payload
0xD8	0x04	crc