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mvpd_partition_structure.md

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This file describes MVPD partition internal structure

TOC

At the begining of MVPD partition Table Of Content is placed. It includes names and addresses of Records counting from the begining of the partition, but not including checksums. TOC can have up to 32 entries, but only 20 are filled by Hostboot.

struct toc_def {
  char recordName[4],
  record* recordAddress,  // Little Endian
                          // Offset from the beginning of partition.
                          // Doesn't include checksums.
                          // Remember to account for that if present
                          // or remove checksums using ecc tool.
  uint16_t unused,
};

toc_def TOC[32];

Record

Each Record includes some kind of address which purpouse is yet unknown, RT Keyword holding 1 byte of data, string name of the record and an array of Keywords which can be as long as the space before the next Keyword beginning.

Following records are present in MVPD after Hostboot has filled the partition:
CP00, CRP0, LRP0, LRP1,
LRP2, LRP3, LRP4, LRP5,
LWP0, LWP1, LWP2, LWP3,
LWP4, LWP5, MER0, VER0,
VINI, VMSC, VRML, VWML
It is unknown if other Keyword names could also be present in MVPD.

struct record {
  uint16_t address;
  keyword RTKeyword(    // This Keyword is always present
    char recordName[4] // and holds Record name as data.
  );
  keyword keywords[];    // Can hold any amount of Keywords.
};

Keyword

There are two possible types of Keywords. Pound and Non-Pound ones. In each case the structure is a bit different and Pound Keywords can be larger.

Only some defined Keywords names are valid.

Possible Keyword names:
20, 21, 30, 31, AW, CC,
CE, CH, CT, DD, DN, DR,
ED, FN, HE, HW, IN, IQ,
L1, L2, L3, L4, L5, L6,
L7, L8, PB, PG, PK, PM,
PN, PR, PZ, RT, SB, SN,
TE, VD, VZ

Possible Pound Keyword names:
#G, #H, #I, #M, #R, #V, #W

struct keyword {
  char keywordName[2];
  uint8_t keywordSize; // Little Endian
                       // Doesn't include checksums.
  char data[keywordSize];
};

struct pound_keyword {
  char keywordName[2];  // NOTE must include leading '#'
  uint16_t keywordSize; // Little Endian
                        // Doesn't include checksums.
  char data[keywordSize];
};

Ring

Some of the keywords contain structures called Ring. This structure is compressed usign RS4 algorithm and has a header of following structure.

struct CompressedScanData {
    uint16_t iv_magic;    // Always "RS"
    uint8_t  iv_version;
    uint8_t  iv_type;
    uint16_t iv_size;     // Big Endian
                          // Includes this structure and data after.
                          // Doesn't include checksums.
    RingId_t iv_ringId;   // This is used to recognize correct Ring
    uint32_t iv_scanAddr;
    char data[]
};