Cid Decoder _hot_ - Emmc

Let us decode a real-world 32-character example string: 150100414a343561320251a37c02b1bf Raw Hex: 15 01 00 41 4a 34 35 61 32 02 51 a3 7c 02 b1 bf Step 1: Parsing the Manufacturer ID (MID) : 0x15

| Byte (offset) | Field | Name | Size (bits) | Description | | :--- | :--- | :--- | :--- | :--- | | 15 | MID | Manufacturer ID | 8 | Unique JEDEC-assigned ID | | 14 | CBX | Card/BGA | 2 | Package type (BGA / removable) | | 13-12 | OID | OEM/Application ID | 16 | OEM identifier (optional) | | 11-8 | PNM | Product Name | 32 | ASCII string (6 chars, left-justified, space-padded) | | 7 | PRV | Product Revision | 8 | Major/Minor BCD (e.g., 0x12 = v1.2) | | 6-4 | PSN | Product Serial Number | 24 | Unique device serial number | | 3-2 | MDT | Manufacturing Date | 12 | Year (BCD) + Month (BCD) | | 1-0 | CRC | CID CRC | 7+1 | Checksum (7 bits) + 1 reserved bit |

Technicians replacing corrupted storage chips in Android devices or automotive infotainment systems (like Tesla MCU units) use CID decoders to verify replacement chip compatibility. Some device bootloaders strictly validate the CID string; using an incompatible or counterfeit chip can permanently brick the device. Counterfeit Detection

# 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 emmc cid decoder

The eMMC (embedded MultiMediaCard) CID (Card Identification) decoder is a tool used to extract and decode the CID register from an eMMC device. The CID register contains essential information about the eMMC device, such as its manufacturer, device type, and serial number.

Most modern decoders exist as web-based tools or command-line utilities. A user typically retrieves the raw CID string from a device (for example, via /sys/block/mmcblkX/device/cid in Linux) and pastes it into the decoder. The software then performs bitmasking and ASCII conversion to present a structured table of the chip's internal identity.

A unique tracking ID assigned to this individual silicon die. 6. Manufacturing Date (MDT) Hex Byte: a1 Let us decode a real-world 32-character example string:

cat /sys/block/mmcblk0/device/cid

‎07-03-2017 02:13 AM. JohnU. Contributor III. Hi, Patch proposal for SDK 2.2.0 (LPCXpresso54608): Date: Fri Jun 30 13:37:31 2017 + NXP Community MultiCID Decoder

Split into major and minor hardware revision numbers (4 bits each). (Product Serial Number) Check spec

45010053454d303447d301d4935400b2

This report explains the structure and decoding process for the eMMC Card Identification (CID) register, provides decoding algorithms, example decodes, and a small reference implementation in Python to parse a 128-bit CID value into human-readable fields.

Just provide the CID string and I'll do the decoding for you! eMMC Flash Chips Explained - NexPCB

Now, let’s decode it using a simple Python snippet or an online tool.

These tools allow you to paste a 16-byte (32-character) hex string to instantly view the internal data: MultiCID Decoder (Gough Lui)