What Is ISP Pinout

ISP (In-System Programming) is a hardware-level technique that allows technicians to communicate directly with the NAND flash storage on the Samsung SM-A70S (SM-A707) motherboard, bypassing the CPU and operating system entirely. By soldering or clamping fine probe wires onto designated test pads — collectively called the ISP pinout — a programmer box can read, write, or erase the device's UFS/eMMC storage at a raw level. For the SM-A707, this method is essential when software-based approaches have failed or are simply unavailable, giving the technician full control over firmware, partition tables, and security partitions without requiring the device to boot.

When to Use ISP

ISP access on the SM-A70S is appropriate in several critical repair scenarios:

  • Hard-bricked device: The phone does not power on, shows no signs of life, and cannot enter Download Mode through normal key combinations.
  • FRP (Factory Reset Protection) lock: The Google account lock cannot be bypassed through software or ADB methods after a factory reset.
  • Corrupted bootloader or firmware: A failed OTA update or interrupted flash has rendered the device unbootable.
  • Security partition damage: The device loops endlessly or fails authentication checks due to a damaged security or EFS partition.
  • IMEI or EFS recovery: Engineering data must be restored after accidental erasure.

SM-A707 ISP Test Points

The SM-A707 uses a UFS 2.1 storage interface. The ISP pads are typically located on the underside of the motherboard near the UFS chip. Because this device uses UFS rather than legacy eMMC, the signal lines differ from older pinouts. Key pads to identify include the UFS data lanes (TX+/TX−, RX+/RX−), reference clock (REF_CLK), reset (RST#), and power rails (VCCQ at 1.8 V and VCC at 2.9 V). Ground pads are distributed across the board. Exact pad coordinates vary by board revision and should be confirmed with a verified schematic or board-view file before probing.

Connecting to the Device

Follow this procedure carefully when establishing an ISP connection on the SM-A707:

  • Fully disassemble the device and remove the motherboard from the chassis.
  • Identify the UFS ISP test pads using a verified schematic or board-view reference for the SM-A707.
  • Clean the pad surfaces with IPA and allow them to dry completely.
  • Solder or clamp the ISP adapter/probe wires to CLK, DATA lanes, RST, VCC, VCCQ, and GND pads using 30 AWG wire or a compatible ISP clip.
  • Connect the programmer box (e.g., EasyJTAG Plus or UFi Box) to a PC via USB.
  • Launch the corresponding software, select the correct UFS chip type, and run detection before performing any read or write operation.

Safety Tips and Precautions

Working at the ISP level carries significant risk of permanent board damage if precautions are ignored:

  • Voltage accuracy: The UFS chip requires precise voltages (VCC 2.9 V, VCCQ 1.8 V). Supplying incorrect voltages will destroy the storage IC instantly.
  • ESD protection: Always wear an anti-static wrist strap and work on a grounded ESD mat. A single static discharge can corrupt or kill the UFS chip.
  • No power during soldering: Never apply board power while soldering ISP wires. Solder, inspect, then connect the programmer.
  • Backup before writing: Always perform a full read/backup of the UFS contents before attempting any erase or write operation.
  • Short solder joints: Keep wire connections as short as possible to reduce signal noise on high-speed UFS lanes.

Pin / Test Point Reference

PinDescription
TX+UFS differential transmit positive lane — Exact pad location requires board-view confirmation for A707
TX−UFS differential transmit negative lane — Exact pad location requires board-view confirmation for A707
RX+UFS differential receive positive lane — Exact pad location requires board-view confirmation for A707
RX−UFS differential receive negative lane — Exact pad location requires board-view confirmation for A707
REF_CLKUFS reference clock signal pad — Typically 19.2 MHz; verify with schematic
RST#UFS active-low reset signal pad
VCCPrimary power supply for UFS chip — 2.9 V — Do not exceed rated voltage
VCCQI/O power supply for UFS chip — 1.8 V — Do not exceed rated voltage
GNDCommon ground reference — multiple pads on board

Tools required: EasyJTAG Plus with UFS adapter, UFi Box, Medusa Pro II, RIFF Box 2, 30 AWG insulated wire or ISP probe clip, Anti-static wrist strap and ESD mat, Regulated bench power supply, Microscope or magnification loupe, Isopropyl alcohol (99%) and lint-free swabs

Supported operations: Read Firmware / Full UFS Backup, FRP Erase, Dead Boot Repair, Firmware Write / Restore, IMEI / EFS Repair, Security Partition Erase, Bootloader Repair

⚠ Safety note: UFS rails are 2.9 V (VCC) and 1.8 V (VCCQ). Wrong voltage permanently destroys the storage IC. Always backup before writing. Use ESD protection at all times.