What Is ISP Pinout

ISP (In-System Programming) is a hardware-level access method that allows technicians to communicate directly with a device's NAND flash storage — bypassing the main CPU boot process entirely. By soldering or probing specific test points on the motherboard, a compatible box or adapter can read, write, or erase flash data at the chip level. This technique is essential when standard software methods fail, such as when a device refuses to boot, is locked by FRP (Factory Reset Protection), or has a corrupted bootloader. ISP access on the Samsung SM-A Quantum (A716S) targets the UFS flash interface pads, enabling direct NAND operations through specialized hardware tools.

SM-A716S ISP Pinout Map

The Samsung SM-A Quantum (A716S) uses a UFS 2.1 flash storage interface. The critical ISP test points are located on the rear side of the main PCB, typically near the UFS flash chip. Technicians must identify and use the following signal lines:

  • CLK (Clock): Provides the timing reference signal for UFS data transfer.
  • DAT0 (Data Line 0): Primary bidirectional data line for UFS communication.
  • CMD (Command): Carries command and response data between host and flash.
  • VCC (Power): Core supply voltage for the UFS flash chip (typically 2.9V–3.0V).
  • VCCQ (I/O Power): I/O interface voltage for UFS signaling (typically 1.8V).
  • GND (Ground): Common ground reference point.
  • RST (Reset): Hardware reset line for the UFS controller.

Note: Exact pad coordinates and silkscreen labels on the A716S PCB should be verified using a high-resolution board schematic or a confirmed ISP pinout diagram before soldering. Pad positions may vary slightly between PCB revisions.

When Technicians Use ISP

ISP access on the A716S is typically required in three primary scenarios. First, dead boot repair — when the device shows no signs of life after a failed firmware flash or power surge, ISP allows direct firmware restoration to the UFS chip. Second, pattern lock or FRP bypass — when the device is locked and ADB or download mode is inaccessible, ISP enables direct erasure of lock data or user partition. Third, eMMC/UFS recovery — when flash storage corruption prevents normal operation, ISP tools can perform sector-level read/write operations to restore functionality without requiring chip removal.

Accessing the Test Points

Follow this procedure carefully when connecting ISP on the A716S:

  • Fully disassemble the device and remove the motherboard safely.
  • Clean the target PCB area around the UFS chip using isopropyl alcohol (99%).
  • Using a microscope, identify the CLK, DAT0, CMD, VCC, VCCQ, GND, and RST test pads.
  • Solder thin magnet wire (30–36 AWG) to each test point or use a compatible ISP probe jig.
  • Connect wires to your ISP adapter (e.g., EasyJTAG Plus UFS socket or UFI Box UFS adapter).
  • Power the board via the ISP tool's regulated supply — do not connect the battery during ISP operations.
  • Launch the appropriate software, select SM-A716S or Snapdragon 765G profile, and begin the required operation.

Safety Tips and Warnings

ISP work on the A716S carries significant risk if proper precautions are not observed:

  • Voltage accuracy is critical: VCC must not exceed 3.0V and VCCQ must not exceed 1.8V. Incorrect voltage will permanently damage the UFS chip.
  • ESD protection: Always use an anti-static wrist strap and mat. UFS flash chips are highly sensitive to electrostatic discharge.
  • No battery during ISP: Never connect the battery while probing or powering via ISP adapter.
  • Back up before writing: Always perform a full UFS read/backup before attempting any erase or write operation.
  • Verify pinout: Confirm test pad assignments with a trusted schematic before making contact — reversed connections can cause irreversible damage.

Pin / Test Point Reference

PinDescription
CLKUFS clock signal line — Verify exact pad location on PCB revision
DAT0Primary UFS bidirectional data line — Verify exact pad location on PCB revision
CMDUFS command and response line — Verify exact pad location on PCB revision
VCCUFS core power supply, typically 2.9V–3.0V
VCCQUFS I/O interface voltage, typically 1.8V
GNDCommon ground reference
RSTHardware reset line for UFS controller — Verify exact pad location on PCB revision

Tools required: EasyJTAG Plus with UFS adapter, UFI Box, UMT (Ultimate Multi Tool), Medusa Pro II, ISP probe jig or 30–36 AWG magnet wire, Microscope, Hot air station / fine-tip soldering iron, Regulated bench power supply

Supported operations: Read Firmware, Write Firmware, FRP Erase, Dead Boot Repair, UFS Full Backup, User Data Erase, Bootloader Repair

⚠ Safety note: UFS VCC must not exceed 3.0V; VCCQ must not exceed 1.8V. Always use ESD protection. Never connect battery during ISP. Verify all pad assignments before contact.