What Is ISP Pinout

ISP (In-System Programming) is a hardware-level technique that allows technicians to communicate directly with a device's eMMC or UFS storage chip by accessing dedicated test points on the printed circuit board. Unlike software-based methods, ISP bypasses the application processor entirely, meaning it works even when the device will not boot, has a corrupted bootloader, or is locked behind FRP (Factory Reset Protection). By soldering or pressing fine-tipped probes onto specific test pads, a compatible box or dongle reads and writes raw NAND data directly. For the Samsung SM-A326 5G, ISP is one of the most reliable paths to recovery when conventional USB-based flashing is unavailable.

SM-A326 ISP Test Point Map

The Samsung SM-A326 5G uses a UFS 2.1 storage interface rather than a traditional eMMC bus. The ISP test points are located on the back side of the main PCB, typically clustered near the UFS storage IC. The standard UFS ISP signals required are listed below. Due to UFS protocol differences from eMMC, the relevant lines are RCLK, BCLKP/N, DATA0P/N, and RESETN alongside VCC and GND references.

  • CLK (RCLK): Reference clock line to the UFS controller
  • DATA0P / DATA0N: Differential data pair, positive and negative
  • BCLKP / BCLKN: Burst clock differential pair
  • RESETN: Active-low reset line for the UFS device
  • VCC: Core supply voltage (2.7–3.6 V)
  • VCCQ: I/O supply voltage (1.2 V)
  • GND: Ground reference

Note: Exact pad coordinates and silk-screen labels on the A326 PCB are not universally published. Always cross-reference a verified PCB diagram before probing.

When To Use ISP Method

ISP access is appropriate in the following scenarios:

  • Device is completely dead and does not enter Download Mode or EDL
  • Bootloader is corrupted and USB is non-functional
  • FRP lock cannot be cleared by any software or ADB method
  • IMEI or NV data restoration is required at partition level
  • Pattern/PIN lock removal when no other method succeeds

ISP Access Procedure

Follow these steps carefully to establish a successful ISP connection on the SM-A326:

  1. Fully disassemble the device and remove the main PCB from the chassis.
  2. Disconnect the battery connector and all flex cables.
  3. Identify the UFS ISP test points using a verified PCB reference diagram.
  4. Connect your ISP tool (EasyJTAG Plus or UMT ISP adapter) to the appropriate pads using probe hooks or fine-gauge wire.
  5. Supply regulated 3.3 V to VCC and 1.2 V to VCCQ via the tool's power rails — do not use the device battery.
  6. Open your box software, select Samsung SM-A326 or MT6853 UFS profile, and initiate the read or erase operation.
  7. Once complete, safely disconnect all probes before restoring power to the board.

Safety Tips and Precautions

Working at the ISP level carries significant risk of permanent damage if done incorrectly:

  • Always verify voltage levels with a multimeter before connecting — overvoltage will destroy the UFS chip instantly.
  • Remove the battery before probing; never attempt ISP with the battery connected.
  • Use fine-tipped probes and avoid bridging adjacent pads; short circuits on differential pairs can render the storage unreadable.
  • Back up a full eMMC/UFS dump before performing any write or erase operation.
  • Work in a static-safe environment — use an anti-static mat and wrist strap.
  • If in doubt about pad identification, consult a second verified source before touching the PCB.

Pin / Test Point Reference

PinDescription
CLK (RCLK)Reference clock line for UFS interface — Exact pad location unconfirmed — verify with PCB diagram
DATA0PUFS differential data line, positive — Exact pad location unconfirmed
DATA0NUFS differential data line, negative — Exact pad location unconfirmed
BCLKPUFS burst clock, positive differential — Exact pad location unconfirmed
BCLKNUFS burst clock, negative differential — Exact pad location unconfirmed
RESETNActive-low reset signal to UFS device — Exact pad location unconfirmed
VCCCore supply voltage for UFS chip, typically 2.7–3.6 V
VCCQI/O supply voltage for UFS chip, typically 1.2 V
GNDGround reference — multiple points available on PCB edge

Tools required: EasyJTAG Plus with UFS ISP adapter, UMT (Ultimate Multi Tool) ISP module, Medusa Pro II, Fine-tip ISP probe hooks or 30 AWG wire, Regulated bench power supply, Multimeter

Supported operations: FRP Erase, Dead Boot Repair, Read Firmware / Full UFS Dump, Write Firmware, IMEI Restoration, Pattern / PIN Lock Removal, Partition-level Data Recovery

⚠ Safety note: Never connect ISP probes with the battery attached. Verify VCC (3.3 V) and VCCQ (1.2 V) with a multimeter before powering on. Overvoltage or incorrect pinout will permanently destroy the UFS storage chip.