eMMC CID Decoder: A Technical Overview Card Identification (CID)
register is a 16-byte (128-bit) unique identifier embedded in every eMMC (embedded Multi-Media Card)
chip. It serves as a permanent digital fingerprint, containing manufacturing details crucial for device security, firmware validation, and hardware repair. Prodigy Technovations 1. CID Register Structure According to the JEDEC JESD84-B51
standard, the CID is transmitted in a 136-bit response (R2) during the device identification phase. The 128 bits of actual data are partitioned as follows: Prodigy Technovations Field Name Description (Manufacturer ID) Unique code for the manufacturer (e.g., Samsung: , SK Hynix: (Device/BGA) Indicates the package type or device category. Assigned to the Original Equipment Manufacturer. (Product Name) 6 ASCII characters representing the model (e.g., "JS04AC"). (Product Revision) Hardware and firmware revision versions. (Product Serial Number) A strictly unique serial number. (Manufacturing Date) Encodes the month and year of production. (Checksum) Error detection code to ensure data integrity. 2. Decoding Methods
Decoding involves extracting the raw hex string and mapping it to the fields above. Linux Systems
: For devices with an eMMC slot (like a Chromebook or Rock Pi), you can read the CID directly from the sysfs interface: cat /sys/block/mmcblkX/device/cid Hardware Tools : Specialized tools like the Easy JTAG Plus
are commonly used in mobile repair to read and sometimes "repair" (emulate) CID data when replacing chips. Manual Calculation : Converting the 48-bit field from hex to ASCII reveals the readable model name. Suntsu Electronics 3. Practical Applications eMMC Protocol - Prodigy Technovations
The Ultimate Guide to Understanding and Using an eMMC CID Decoder
If you’ve ever dabbled in Android development, automotive GPS updates, or digital forensics, you’ve likely bumped into a cryptic string of 32 hex characters known as the CID. To the uninitiated, it looks like gibberish. To a pro, it’s the DNA of a storage device.
An eMMC CID decoder is the essential tool that translates this hexadecimal string into human-readable data. Here is everything you need to know about what it is, why it matters, and how to use one. What is an eMMC CID?
eMMC (Embedded MultiMediaCard) is the standard storage used in smartphones, tablets, and many automotive infotainment systems. Every eMMC chip has a Card Identification (CID) Register.
The CID is a 128-bit (32-character) unique identifier programmed into the chip during manufacturing. It contains critical metadata, including:
Manufacturer ID (MID): Who made the chip (e.g., Samsung, SanDisk, SK Hynix).
OEM/Application ID (OID): The specific project or entity the chip was built for. Product Name (PNM): The model name (usually 6 characters). Product Revision (PRV): Hardware and firmware version.
Serial Number (PSN): A unique 32-bit number for that specific unit.
Manufacturing Date (MDT): The month and year the chip left the factory. Why Use an eMMC CID Decoder?
Decoding this string isn't just for curiosity. It’s a necessity in several technical fields: 1. Verification of Genuine Hardware
Counterfeit storage is rampant. By running a CID through a decoder, you can verify if a "Samsung" chip actually reports a Samsung Manufacturer ID (0x15). If the CID points to a generic or unknown vendor, you’ve likely found a fake. 2. Automotive and Navigation Updates emmc cid decoder
Many car manufacturers (like VW, Mazda, or Mercedes) tie their GPS maps to the CID of the SD card or eMMC. To update maps or create backups, enthusiasts use a decoder to ensure the CID matches the vehicle's security whitelist. 3. Digital Forensics
In data recovery and forensics, the CID provides a "birth certificate" for the device. It helps investigators establish a chain of custody and identify the exact hardware specifications of a device under examination. 4. Firmware Patching and Development
Developers often need the CID to identify specific hardware "stepping" or revisions to ensure they are flashing the correct bootloader or kernel. How to Use an eMMC CID Decoder
Using a decoder is typically a two-step process: Retrieval and Translation. Step 1: Get the Raw CID
On a rooted Android device or a Linux system, you can usually find the CID by navigating to the sysfs interface. Use the following command in a terminal:cat /sys/block/mmcblk0/device/cid Step 2: Decode the Hex
Once you have the 32-character string (e.g., 1501004d414732474300441234567812), you input it into an eMMC CID Decoder.
Web-Based Decoders: There are several free online tools where you simply paste the string and hit "Decode."
Manual Decoding: If you’re feeling brave, you can follow the JEDEC eMMC standard (JESD84-B51) to manually parse the bits. For example, the first two characters represent the MID, and the next two represent the OID. Common Manufacturer IDs (MID)
When your decoder spits out a result, here are a few common IDs you might see: 0x02: SanDisk/Western Digital 0x11: Toshiba 0x13: Micron 0x15: Samsung 0x45: SanDisk 0x90: SK Hynix
An eMMC CID decoder is a powerful window into the hardware of your device. Whether you are trying to verify a replacement part, update your car’s navigation, or perform deep-level system debugging, understanding how to read the CID is a vital skill in the modern hardware landscape.
Do you have a specific CID string you're trying to parse, or
eMMC CID (Card Identification) decoder is a tool or script used to translate the raw 128-bit hexadecimal string stored in an eMMC device's CID register into human-readable information. This register serves as a unique "fingerprint" for the storage chip, containing essential manufacturing and device-specific metadata. The Role of the CID Register
The CID is a mandatory register in all JEDEC-compliant eMMC devices. It is primarily used by system developers, repair technicians, and forensic analysts to: www.chipstar.ru Verify Authenticity
: Confirm if a chip is from a genuine manufacturer like Samsung, Micron, or SK Hynix. Debug Hardware
: Identify specific silicon revisions or production dates that may be prone to failure. Match Components
: Ensure the eMMC's unique ID matches the expected ID programmed into a device's CPU, a common security measure in smartphones. Decoded Fields and Their Meaning A standard eMMC CID string contains several defined fields: MID (Manufacturer ID)
: An 8-bit ID assigned by the JEDEC committee to the chip maker. OID (OEM/Application ID) eMMC CID Decoder: A Technical Overview Card Identification
: A 16-bit identifier for the original equipment manufacturer or specific application. PNM (Product Name)
: A 6-character ASCII string representing the model name (e.g., "MAG2GA"). PRV (Product Revision)
: A 2-digit BCD code indicating the hardware and firmware version. PSN (Product Serial Number) : A unique 32-bit integer assigned during production. MDT (Manufacturing Date) : Encoded year and month of production. : A checksum used to verify the integrity of the CID data. How to Extract and Decode CID Data
To decode a CID, you must first read the raw hex string from the device:
The eMMC Card Identification (CID) register is a 128-bit, JEDEC-standardized register containing critical metadata—such as manufacturer ID, product name, and manufacturing date—essential for identifying device authenticity. Data is typically retrieved on Linux via sysfs and decoded using tools to parse the 32-character hex string for engineering or forensic analysis. A commonly used online tool is available at MultiCID Decoder. sdmmc eMMC Decode CID properly - NXP Community
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
The eMMC CID (Card Identification) Decoder is a specialized tool used to translate the 128-bit hexadecimal string stored in an eMMC (Embedded MultiMediaCard) into human-readable technical data. This identification register is a fundamental component of flash storage management, providing critical metadata about the chip's origin, hardware specifications, and manufacturing history. The Role of the CID Register
Every eMMC device contains a CID register, a 16-byte (128-bit) read-only register that is programmed during the manufacturing process. Unlike the user data stored on the chip, the CID is permanent and unique to that specific hardware unit. It serves as the "fingerprint" of the storage device, essential for system bootloaders, kernels, and forensic analysts to identify the exact hardware they are interacting with. Anatomy of an eMMC CID
A CID decoder breaks down the raw hex string into several standardized fields defined by the JEDEC eMMC standards:
Manufacturer ID (MID): An 8-bit value assigned by JEDEC that identifies the chip maker (e.g., 0x15 for Samsung, 0x13 for Micron, 0x45 for SanDisk).
Device/BGA Type (CBX): Indicates whether the device is a single chip or a multi-chip package.
OEM/Application ID (OID): An 8-bit identifier typically used by the manufacturer to identify the customer or a specific product line.
Product Name (PNM): A 6-character ASCII string representing the model name (e.g., "MAG2GA" or "KLMAG4").
Product Revision (PRV): A 1-byte value showing the hardware and firmware revision levels.
Product Serial Number (PSN): A 32-bit unique number assigned to each individual chip.
Manufacturing Date (MDT): A 1-byte field encoding the month and year the chip was produced.
CRC7 Checksum: A 7-bit checksum used to verify the integrity of the CID data during transmission. Applications of eMMC CID Decoding Manufacturer lookup table based on JEDEC JEP106 (available
The ability to decode these values is vital across several technical disciplines:
Forensics and Data Recovery: Investigators use the CID to verify the authenticity of a storage component and ensure that hardware has not been swapped or tampered with.
Hardware Repair and "Emulation": In some specialized electronics repair (such as automotive infotainment or gaming consoles), systems may perform "CID checks." A decoder helps technicians understand the original chip's specs to find a compatible replacement or, in specific cases, configure a programmable chip to match the original ID.
Supply Chain Verification: Companies use CID decoders to audit their hardware components, ensuring that the chips delivered by suppliers match the requested specifications and are not counterfeit or "gray market" parts.
Driver Optimization: Operating system kernels (like Linux) read the CID to apply specific "quirks" or optimizations tailored to a particular manufacturer’s silicon architecture. Using a CID Decoder
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.
In summary, the eMMC CID decoder is an indispensable bridge between raw machine data and actionable hardware intelligence, ensuring transparency and reliability in the complex ecosystem of embedded storage.
def decode_emmc_cid(cid_hex): cid_bytes = bytes.fromhex(cid_hex) if len(cid_bytes) != 16: raise ValueError("CID must be 16 bytes")mid = cid_bytes[15] pnm = cid_bytes[11:7:-1][::-1].decode('ascii').strip() prv_major = (cid_bytes[7] >> 4) & 0x0F prv_minor = cid_bytes[7] & 0x0F psn = int.from_bytes(cid_bytes[6:3:-1], 'big') mdt_raw = (cid_bytes[3] << 8) | cid_bytes[2] year = 2000 + ((mdt_raw >> 4) & 0xFF) month = mdt_raw & 0x0F return "mid": hex(mid), "manufacturer": lookup_manufacturer(mid), "product_name": pnm, "revision": f"prv_major.prv_minor", "serial": psn, "date": f"year-month:02d"
Manufacturer lookup table based on JEDEC JEP106 (available in many open‑source projects).
If the device won't boot, you need an eMMC hardware programmer like:
These tools read the CID directly via the eMMC bus (CLK, CMD, D0) using a soldered or pogo-pin connection.
When building custom firmware (Yocto, Buildroot), decoding the CID helps identify which eMMC chip is present on the target board, ensuring the correct device tree and driver settings.
The CID works alongside the CSD (Card Specific Data) register. While the CID identifies who made the chip, the CSD defines how it operates (read block length, speed, capacity). A full hardware diagnosis requires decoding both.
| Domain | Use Case |
| :--- | :--- |
| Embedded Forensics | Identify counterfeit eMMC chips |
| IoT Device Inventory | Automate hardware asset tracking |
| Bootloader/Uboot | Verify correct storage device before mounting |
| RMA / Warranty | Match returned chip to shipment records |
| Linux /sys/block/mmcblkX/device/cid | User‑space recovery of device info |
Typical eMMC CID structure (MSB → LSB; total 128 bits):
Note: Some vendor cards use different PNM lengths or place fields differently; check device datasheet.