Difference between revisions of "EEPROM"

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m (Make read checksum code more readable)
m (Make checksum code more readable)
Line 332: Line 332:
 
   * Rewritten to ANSI C by David Pye (dmp@davidmpye.dyndns.org)
 
   * Rewritten to ANSI C by David Pye (dmp@davidmpye.dyndns.org)
 
   *
 
   *
−
   * Thanks! */
+
   * Adapted for XboxDevWiki
−
  void EepromCRC(unsigned char *crc, unsigned char *data, long dataLen) {
+
  */
−
        unsigned char* CRC_Data = (unsigned char *)malloc(dataLen+4);
+
  uint32_t EepromCRC(unsigned char *data, long dataLen) {
−
         int pos=0;
+
 
−
         memset(crc,0x00,4);
+
         // Initialize result to zero
 +
         uint8_t crc[4] = { 0x00, 0x00, 0x00, 0x00 };
 
   
 
   
−
        memset(CRC_Data,0x00, dataLen+4);
 
 
         //Circle shift input data one byte right
 
         //Circle shift input data one byte right
−
         memcpy(CRC_Data + 0x01 , data, dataLen-1);
+
        unsigned char* CRC_Data = (unsigned char *)malloc(dataLen + 4);
−
         memcpy(CRC_Data, data + dataLen-1, 0x01);
+
        memset(CRC_Data, 0x00, dataLen + 4);
 +
         memcpy(CRC_Data + 0x01 , data, dataLen - 1);
 +
         memcpy(CRC_Data, data + dataLen - 1, 0x01);
 
   
 
   
−
         for (pos=0; pos<4; ++pos) {
+
        // Calculate checksum
 +
         for (unsigned int i = 0; i < 4; i++) {
 
                 unsigned short CRCPosVal = 0xFFFF;
 
                 unsigned short CRCPosVal = 0xFFFF;
−
                 unsigned long l;
+
                 for (unsigned long l = i; l < dataLen; l += 4) {
−
                for (l=pos; l&lt;dataLen; l+=4) {
 
 
                         CRCPosVal -= *(unsigned short*)(&amp;CRC_Data[l]);
 
                         CRCPosVal -= *(unsigned short*)(&amp;CRC_Data[l]);
 
                 }
 
                 }
−
                 CRCPosVal &amp;= 0xFF00;
+
                 CRCPosVal &= 0xFF00;
−
                 crc[pos] = (unsigned char) (CRCPosVal &gt;&gt; 8);
+
                 crc[i] = (unsigned char) (CRCPosVal << 8);
 
         }
 
         }
 +
 
         free(CRC_Data);
 
         free(CRC_Data);
 +
 +
        return *(uint32_t*)&checksum;
 
  }
 
  }
 
</pre>
 
</pre>

Revision as of 19:01, 5 May 2019

The Xbox EEPROM is a 256 byte non-volatile storage device which contains device-specific information. It is connected via I²C and located on address 0x54. Parts of the EEPROM are encrypted using Kernel/XboxEEPROMKey.

Contents

Start End Notes
0x00 0x13 HMAC_SHA1 Hash
0x14 0x1B RC4 Encrypted Confounder ??
0x1C 0x2B RC4 Encrypted HDD key
0x2C 0x2F RC4 Encrypted Region code
  • 0x01 = North America
  • 0x02 = Japan
  • 0x04 = Europe & Australia
0x30 0x33 Checksum2 - Checksum of next 44 (0x2C) bytes (0x34 - 0x5F)*
0x34 0x3F Xbox serial number - (ASCII chars 0x30 - 0x39 to match each digit in SN)
0x40 0x45 Ethernet MAC address (Microsoft Xbox - 00:50:F2:xx:xx:xx)
0x46 0x47 Unknown Padding ?
0x48 0x57 Online Key ?
0x58 0x5B Video Standard
  • 0x00000000 = not set (INVALID)
  • 0x00400100 = NTSC-M
  • 0x00400200 = NTSC-J
  • 0x00800300 = PAL-I
  • 0x00400400 = PAL-M
0x5C 0x5F Unknown Padding ?
0x60 0x63 Checksum3 - Checksum of the next 92 (0x5C) bytes (0x64 - 0xBF)*
0x64 0x67 Zone Bias - Offset in # minutes to subtract from GMT time

(e.g., for GMT-06 Central; 6hr = 360min = 0x00000168)

0x68 0x6B Standard Timezone Name: 4 characters, NULL fill remainder if shorter (e.g., CST\0, ACST)
0x6C 0x6F Daylight Timezone Name: 4 characters, NULL fill remainder if shorter (e.g., CDT\0, ACDT)
0x70 0x77 Unknown Padding ?
0x78 0x7B Standard Time Starts 10-05-00-02 (Month-Day-DayOfWeek-Hour)
0x7C 0x7F Daylight Savings Time Starts 04-01-00-02 (Month-Day-DayOfWeek-Hour)
0x80 0x87 Unknown Padding ?
0x88 0x8B Standard Timezone Bias; if not DST, 0 (0x00000000) minute time adjust
0x8C 0x8F Daylight Savings Time Bias; if DST, -60 (0xFFFFFFC4) minute time adjust
0x90 0x93 Language ID (0 = not set) 1 byte at offset 0x90 data 4-byte aligned adds the 3 remaining bytes of 0x00
Language EEPROM Value @ 0x90
English 0x01
Japanese 0x02
German 0x03
French 0x04
Spanish 0x05
Italian 0x06
Korean 0x07
Chinese 0x08
Portuguese 0x09
0x94 0x97 Video Settings

Offset 0x96:

  • 0x??=Normal[FIXME]
  • 0xB0=Widescreen
  • 0xB4=Letterbox
0x98 0x9B Audio Settings
0x9C 0x9F Games Parental Control (0 = Max rating) 1 byte at offset 0x9C data 4-byte aligned adds the 3 remaining bytes of 0x00
Xbox Game Rating EEPROM Value @ 0x9C
(RP) Rating Pending (Max) 0x00
(AO) Adults Only 0x01
(M) Mature 0x02
(T) Teen 0x03
(E) Everyone 0x04
(K-A) Kids to Adults 0x05
(EC) Early Childhood 0x06
0xA0 0xA3 Parental Control Passcode; 4 button sequence (each key stored in a nibble)
  • 0x1 = Alt=Digital-Pad-Up or Alt=Left-Thumbstick-Up
  • 0x2 = Alt=Digital-Pad-Down or Alt=Left-Thumbstick-Down
  • 0x3 = Alt=Digital-Pad-Left or Alt=Left-Thumbstick-Left
  • 0x4 = Alt=Digital-Pad-Right or Alt=Left-Thumbstick-Right
  • 0x5 = Alt=A button
  • 0x6 = Alt=B button
  • 0x7 = Alt=X button
  • 0x8 = Alt=Y button
  • 0xB = Left-Trigger
  • 0xC = Right-Trigger
  • 0 = Disabled[FIXME]

Note:[FIXME]

  • EEPROM offset 0xA0: 23 14 00 00
  • Little Endian value 0x00001423.
  • The pass code is D-pad directions up (0x1), right (0x4), down (0x2), left (0x3).
  • Pass code is only 2 bytes not 4, each button is stored as a nibble in the word. First button in the most significant nibble and last in the least significant nibble.
  • Data in the EEPROM is aligned to double word (4-byte) boundaries. Thus, the two extra bytes at 0xA2 and 0xA3 of 0x00.
0xA4 0xA7 Movies Parental Control (0 = Max rating) only 1 byte necessary, the 3 remaining bytes for multiple of 4-byte data alignment[FIXME]
Xbox Movie Rating EEPROM Value @ 0xA4
8 (Max) 0x00
7 (NC-17) 0x01
6 (R) 0x02
5 0x03
4 (PG-13) 0x04
3 (PG) 0x05
2 0x06
1 (G) 0x07
0xA8 0xAB XBOX Live IP Address..
0xAC 0xAF XBOX Live DNS Server..
0xB0 0xB3 XBOX Live Gateway Address..
0xB4 0xB7 XBOX Live Subnet Mask..
0xB8 0xBB Other XBLive settings ?
0xBC 0xBF DVD Playback Kit Zone
0xC0 0xFF Unknown Codes / History ? do not change any values in this region

Note: Info in above table comes from XKUtils XKEEPROM.h.

*Configmagic-FINAL-1.6 uses the wrong size when computing Checksum2 (40 instead of 44 bytes) and Checksum3 (96 instead of 92 bytes). Checksum2 value computed was correct only because the extra 4 bytes not used in the CRC computation were all 0's which does not change the CRC value. However, a similiar problem with computation of Checksum3 is present. The CRC computed for v1.6 Xbox's is incorrect as the 4 extra bytes are not 0's as on earlier versions.

Reading/Writing the EEPROM

Software Method

This is the easiest way to dump an Xbox EEPROM. Use your alternative dashboard to dump the EEPROM to a file and download it over FTP.

Hardware Method

If you cannot dump the EEPROM using software, you can dump it using hardware. You have several options: use an I2C host adapter (see here or here), build an I2C-Serial cable, or use a device like a RaspberryPi which has an I2C interface. Connect SDA/SCL/ground to the LPC pinout on the board. See here for pinout information. Then use the corresponding software to read/write the EEPROM.


The HMAC HDD Key

The HMAC HDD Key is generated out of the first 48 bytes. This section has been identified clearly.


The Region Code

This DWORD is encrypted. It corresponds to the region code in the XBE header:


0x00000001 North America
0x00000002 Japan
0x00000004 Europe / Australia
0x80000000 Manufacturing plant

The MAC address

This is the MAC address of the Ethernet hardware, which has been issued by the IEEE.


DVD Region

This DWORD corresponds to the region code for playback of DVD movies:


0x00000000 None
0x00000001 Region 1
... ...
0x00000006 Region 6

Checksum Algorithm

Checksum2 and Checksum3 values can be calculated by running the following code snippet over the area the checksum covers: 

 /* The EepromCRC algorithm was obtained from the XKUtils 0.2 source released by
  * TeamAssembly under the GNU GPL.
  * Specifically, from XKCRC.cpp
  *
  * Rewritten to ANSI C by David Pye (dmp@davidmpye.dyndns.org)
  *
  * Adapted for XboxDevWiki
  */
 uint32_t EepromCRC(unsigned char *data, long dataLen) {

         // Initialize result to zero
         uint8_t crc[4] = { 0x00, 0x00, 0x00, 0x00 };
 
         //Circle shift input data one byte right
         unsigned char* CRC_Data = (unsigned char *)malloc(dataLen + 4);
         memset(CRC_Data, 0x00, dataLen + 4);
         memcpy(CRC_Data + 0x01 , data, dataLen - 1);
         memcpy(CRC_Data, data + dataLen - 1, 0x01);
 
         // Calculate checksum
         for (unsigned int i = 0; i < 4; i++) {
                 unsigned short CRCPosVal = 0xFFFF;
                 for (unsigned long l = i; l < dataLen; l += 4) {
                         CRCPosVal -= *(unsigned short*)(&CRC_Data[l]);
                 }
                 CRCPosVal &= 0xFF00;
                 crc[i] = (unsigned char) (CRCPosVal << 8);
         }

         free(CRC_Data);

         return *(uint32_t*)&checksum;
 }

Read Checksum Algorithm

When the Xbox reads from the FACTORY_SETTINGS or the USER_SETTINGS section of the EEPROM, this algorithm is ran over the entire section accessed (including the CRC checksum mentioned above) to ensure that the data is valid. If the result of the checksum algorithm does not equal 0xFFFFFFFF, STATUS_DEVICE_DATA_ERROR is returned from the Kernel. 

static uint32_t eeprom_section_checksum(
    const uint32_t* section_data,
    uint32_t section_data_length
)
{
    const uint32_t bitmask = 0xFFFFFFFF;
    uint64_t checksum = 0;
    uint32_t carry_count = 0;

    // Process the data in 32 bit steps
    for(unsigned int i = 0; i < section_data_length / 4; i++) {
        checksum += *section_data;
        if(checksum > bitmask) {
            carry_count++;
            checksum &= bitmask;
        }
        section_data++;
    }
    checksum += carry_count;
    if(checksum > bitmask) {
        checksum += 1;
    }
    return (uint32_t)(checksum & bitmask);
}

Further Reading

Retrieved from "https://xboxdevwiki.net/index.php?title=EEPROM&oldid=6717"