Emmc Cid Decoder ~upd~

#!/usr/bin/env python3 import sys import binascii

# Debian/Ubuntu sudo apt-get install mmc-utils

It’s a 128-bit fingerprint containing:

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. emmc cid decoder

If you have a Linux-based system (like Android), you can often find the raw CID at: /sys/block/mmcblk0/device/cid The Linux Kernel Archives Manual Decoding Logic Industrial eMMC 4.5 Specification - Farnell

Note that this simplified example assumes the CID bytes are arranged in a specific order; the actual bitfield extraction must account for endianness and bit ordering as specified in the JEDEC standard.

: In some cases, replacing a failed eMMC in a device requires matching or transferring the CID of the original chip. Some specialized tools claim to write arbitrary CID values to compatible Samsung eMMC devices, enabling configuration of Samsung eMMCs to emulate other manufacturers' chips—a solution for certain MTK mobile phones with hardcoded CID checks. If you have a Linux-based system (like Android),

| Bits | Field | Name | Description | | :--- | :--- | :--- | :--- | | [127:120] | MID | Manufacturer ID | 8-bit ID assigned by JEDEC (e.g., 0xFE = Samsung, 0x15 = Kingston) | | [119:112] | CBX | Card/BGA (OEM/Application) | Used by the manufacturer | | [111:104] | OID | OEM/Application ID | Identifies the OEM who built the card | | [103:96] | PNM (First 8 bits) | Product Name (Part 1) | First 8 bits of the product name (ASCII) | | [95:88] | PNM (Second 8 bits) | Product Name (Part 2) | | | [87:80] | PNM (Third 8 bits) | Product Name (Part 3) | | | [79:72] | PNM (Fourth 8 bits) | Product Name (Part 4) | | | [71:64] | PNM (Fifth 8 bits) | Product Name (Part 5) | | | [63:56] | PNM (Sixth 8 bits) | Product Name (Part 6) | | | [55:48] | PRV | Product Revision | Major/Minor revision (e.g., 0.1, 3.2) | | [47:40] | PSN (First 8 bits) | Product Serial Number (Part 1) | 32-bit unique serial number | | [39:32] | PSN (Second 8 bits) | Product Serial Number (Part 2) | | | [31:24] | PSN (Third 8 bits) | Product Serial Number (Part 3) | | | [23:16] | PSN (Fourth 8 bits) | Product Serial Number (Part 4) | | | [15:12] | MDT | Manufacturing Date | Year/Month of production | | [11:8] | (Reserved) | Reserved | Set to zero | | [7:1] | CRC | CRC7 | 7-bit checksum of CID fields | | [0] | (Reserved) | Always 1 | Fixed value |

Let’s decode a real CID from a SanDisk eMMC used in a Chromebook.

result = {} for name, (high, low) in fields.items(): mask = (1 << (high - low + 1)) - 1 value = (cid_int >> low) & mask result[name] = value | Bits | Field | Name | Description

On Android (rooted):

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Developers often need to bind software licenses to a hardware ID. Since the CID is immutable, it is a better hardware fingerprint than MAC addresses (which can be spoofed). Decoding allows scripts to read /sys/block/mmcblk0/device/cid and extract the serial number or manufacturer.