Emmc Cid Decoder ❲Validated❳

An eMMC CID (Card Identification) decoder is a tool or script used to translate the 128-bit raw hex data from an embedded MultiMediaCard's CID register into human-readable information about the device's hardware identity. This information is critical for firmware developers and hardware hackers to verify the authenticity and specifications of a flash chip. CID Register Overview

3. Forensic Data Recovery

When performing data recovery on a dead eMMC, the CID provides critical metadata. Forensic tools use the CID to validate that the dumped data matches the original chip, ensuring data integrity in legal cases. emmc cid decoder

7. Python reference decoder (example)

# Python 3 example: parse 128-bit CID hex string (big-endian bytes)
def parse_cid(cid_hex):
    b = bytes.fromhex(cid_hex)
    if len(b) != 16:
        raise ValueError("CID must be 16 bytes")
    val = int.from_bytes(b, 'big')
    def get(bits_high, bits_low):
        width = bits_high - bits_low + 1
        return (val >> bits_low) & ((1 << width) - 1)
    # offsets (bit positions where 0 is LSB)
    mid = get(127,120)
    oid = get(119,104)
    pnm = get(103,64)
    prv = get(63,56)
    psn = get(55,24)
    mdt = get(23,12)
    crc  = get(11,5)
    end  = get(0,0)
    # decode ascii fields
    oid_str = oid.to_bytes(2,'big').decode('ascii',errors='replace')
    pnm_str = pnm.to_bytes(5,'big').decode('ascii',errors='replace')
    prv_major = (prv >> 4) & 0xF
    prv_minor = prv & 0xF
    # MDT: year offset high 8 bits, month low 4 bits — many eMMC: year = 1997 + year_offset? Check spec.
    year = 2000 + ((mdt >> 4) & 0xFF)
    month = mdt & 0xF
    return 
        "MID": mid, "OID": oid_str, "PNM": pnm_str,
        "PRV": f"prv_major.prv_minor", "PSN": psn,
        "MDT": "year": year, "month": month, "CRC7": crc, "end": end

| Byte | Val | Field | Decoded |
|------|-----|-------|---------|
| 15 | 0x15 | MID | Samsung |
| 14 | 0x01 | CBX | BGA |
| 13-12 | 0x00 0x4D | OID | 0x004D (undefined) |
| 11-8 | 0x34 0x47 0x42 0x55 | PNM | "4GBU" ("4GB" class device) |
| 7 | 0x01 | PRV | v0.1 (BCD 0x01) |
| 6-4 | 0x5A 0x1A 0xC0 | PSN | 5903040 (decimal) |
| 3-2 | 0xE8 0x01 | MDT | Aug 2018 (0xE8=year 18, 0x01=Jan? see note) | An eMMC CID (Card Identification) decoder is a