did anyone try to read the data on the nor flash?

Question

Accepted Answer

Direct answer to the question - Yes. Reading data from NOR flash is routine in debugging, firmware backup, forensics, and reverse engineering. - It is commonly done in-circuit via the device’s bootloaderOS or debug port, or off-board with a flash programmer if needed. Detailed problem analysis - Access paths least to most invasive - Via bootloaderOS: If the device exposes a console UARTUSB or runs LinuxRTOS, use built‑in tools. Examples: in U‑Boot use sf probe; sf read , then transfer the buffer over UARTEthernet; in Linux use procmtd to identify partitions and dd if=devmtdX of=tmpdump.bin. - Via CPU debug: Halt the CPU with JTAGSWD and dump the memory‑mapped NOR typical for XIP designs. Tools: OpenOCD, J‑Link. Beware of cachesMPU and address remaps; disable caches or read uncached windows when possible. - Bus sniff or in‑circuit read: For SPIQSPI parts, clip onto the SOIC‑8WSON package CS, CLK, IO0MOSI, IO1MISO, IO2‑IO3 for QSPI, VCC, GND, WP, HOLD. Hold the SoC in reset or tristate its pins to avoid bus contention. Use a level‑correct reader 1.8 V or 3.3 V. - Chip‑off: Desolder and read in a socket with a universal programmer when in‑circuit methods fail or security circuitry on the board interferes. - Protocol specifics that matter - Identify the device first: read JEDEC ID with command 0x9F; then read SFDP 0x5A to discover supported opcodes, addressing 2432‑bit, and dummy cycles. - Choose a safe read opcode: legacy 0x03 no dummy cycles is slow but universal; fast reads 0x0B, 0x3B0x6B QSPI, DTRDDR octal require correct dummy cycles per SFDP. - Address width: devices ≥16 MiB typically require 32‑bit addressing enter 4‑byte mode or use 0x13 fast‑read with embedded 32‑bit address. - XIPQSPI mapping: On systems executing‑in‑place, the external flash appears in the CPU’s memory map; dumping that region is equivalent to reading flash directly. - Protection and why a dump can still fail - Block protection: BPSecSRP bits may lock sectors; clear with write‑enable + status register writes if allowed; WP pin low can hard‑protect. - Security registersOTP: Small secure regions may be one‑time‑programmable and not erasable, but they are usually still readable. - SoC‑side encryptionsecure boot: Many MCUsSoCs e.g., ESP32, i.MX RT, some STM32 with OEM secure boot support on‑the‑fly decryption. The raw NOR contents will then be encrypted; only the CPU sees plaintext. - Board interference: Parallel pull‑upsdowns, series resistors, and an active SoC can corrupt in‑circuit reads. Isolate power, assert reset, or lift CS to the SoC. - Electricalsignal integrity considerations - Voltage: Most SPIQSPI NOR is 1.8 V or 3.3 V; 5 V is uncommon. Use proper level shifting; do not attach 3.3 V tools to 1.8 V parts. - Clocks and wires: Keep clip leads short; start with low SPI clock 100 kHz–1 MHz and increase once stable. For DTRDDR octal modes, prefer a dedicated programmer. - Data validation and analysis - Verify with repeated reads and hashes; check for recognizable headers bootloader strings, filesystem magic such as JFFS2CRAMFSSquashFSUBI. - Use tools like binwalk, strings, and file system unpackers to parse partitions; preserve original binary dumps as read‑only artifacts. Current information and trends - Interface trends: Migration from classic SPIQSPI to Octal SPI OSPIOPI, often 1.8 V with DTRDDR and higher dummy‑cycle sensitivity; widespread SFDP support allowing software‑discoverable timing and opcodes. - Security trends: Default enablement of secure bootflash encryption on newer platforms; expect ciphertext in raw dumps and authenticated boot images that resist modification. - Capacity and addressing: Larger densities 256 Mb–2 Gb are common; 32‑bit addressing and 4‑byte mode are the norm for ≥128 Mb devices. Supporting explanations and details - Typical minimal workflow in‑circuit, SPI NOR - Identify part marking; get the datasheet; confirm VCC. - Isolate the bus hold SoC in reset, pull its CS high via resistor, or remove series resistor. - Connect a level‑correct reader; read RDID 0x9F and SFDP 0x5A. - Start with opcode 0x03 reads; incrementally dump the address space; then switch to fast read once dummy cycles are known. - Repeat read and compare; if unstable, reduce clock, shorten leads, or fully power the board from a lab supply. - Typical minimal workflow JTAGXIP - Halt CPU, locate the external flash window in the memory map, disable caches, dump the region to a file. Ethical and legal aspects - Only access firmware you are authorized to read. Circumventing technical protection measures or extracting third‑party secrets may violate laws e.g., anti‑circumvention and contractswarranties. Handle any personal data found in dumps per privacy regulations. Practical guidelines - Tools that reliably work - Software: flashrom broad device support, OpenOCD, vendor tools, sigrokPulseView, binwalk. - Hardware: level‑switchable USB programmers 3.3 V1.8 V, SOIC‑8WSON test clips, FT2232H‑based SPI bridges, logic analyzers, J‑LinkOpenOCD adapters. - Quick triage checklist - Part number and voltage known? - Bus isolated from host SoC? - RDID and SFDP readable? - Correct address width and dummy cycles configured? - Stable power and short wiring? - Common pitfalls and remedies - Reads return 0xFF0x00 sporadically: lower SPI clock, shorten leads, ensure CS integrity. - Only the SoC can read plaintext: likely on‑the‑fly decryption; use a software path on the device bootloaderOS instead of raw bus reads. Possible disclaimers or additional notes - Some packages WSONBGA are hard to clip; chip‑off may be the only option. - Vendor‑specific opcodes enterexit 4‑byte mode, deep power‑down vary; always confirm against the actual datasheet or SFDP table. Suggestions for further research - Look up the device’s JESD216 SFDP parameter table and the exact datasheet for statusconfiguration register layout. - Review your SoC’s bootflash controller manual for XIP mapping and any inline encryption. - Explore platform‑specific communities e.g., MCUvendor forums for known quirks with your exact flash and controller. Brief summary - Yes—NOR flash is routinely read both in‑system and off‑board. Start with the least invasive path bootloaderOS, move to debugbus access, and use chip‑off as a last resort. Pay attention to voltage, bus isolation, addressdummy‑cycle configuration, and possible SoC‑side encryption. If you share the exact part number, interface SPIQSPIparallel, and your tools, I can give step‑by‑step instructions for your device.

Reading Data from NOR Flash: Methods, Tools, and Security Considerations

User question

Artificial Intelligence Response

Ask additional question