What Is ISP Pinout

ISP (In-System Programming) pinout is a direct hardware access method that allows technicians to communicate with the eMMC storage chip on the Samsung Galaxy A9 Pro 2016 (SM-A910) without removing it from the PCB. By connecting specialized equipment directly to exposed test pads on the motherboard, a technician can read, write, or erase firmware data at the chip level. This bypasses the device's operating system entirely, making it invaluable when the phone cannot boot or when software-based tools fail to establish a connection. For the SM-A910, ISP access is the most reliable path to resolving deep software faults, FRP locks, and corrupted bootloaders.

SM-A910 ISP Pinout Diagram

The ISP test points on the SM-A910 motherboard correspond to the standard eMMC 5.1 bus signals. These pads are typically located on the back side of the PCB, near the eMMC chip. The key signal lines required are CLK (clock), CMD (command), DAT0 (data line 0), VCC (power supply to eMMC, 3.3V), VCCQ (I/O voltage, 1.8V), and GND (ground). Some procedures also utilize DAT1–DAT3 for faster 4-bit bus operations.

  • CLK – Clock signal, synchronizes data transfer between host and eMMC
  • CMD – Command line for sending instructions to the eMMC chip
  • DAT0 – Primary data line; minimum required for 1-bit mode operations
  • VCC – 3.3V power rail supplying the eMMC chip
  • VCCQ – 1.8V I/O voltage rail for signal logic
  • GND – Common ground reference

Exact pad coordinates on the SM-A910 PCB have not been independently verified in this reference and are marked uncertain. Technicians should cross-reference a verified PCB diagram or confirmed board photo before probing.

When Technicians Use This Method

ISP pinout access on the SM-A910 is typically required in the following scenarios: dead boot where the device shows no response to normal flashing tools via USB, hard-bricked state after a failed OTA or manual firmware update, FRP (Factory Reset Protection) lock that cannot be bypassed through software, forgotten screen lock with no accessible recovery mode, and eMMC read/backup operations before attempting risky repairs. This method is especially useful when the Qualcomm EDL (Emergency Download) mode is inaccessible or the USB port is physically damaged.

Step-by-Step Access Procedure

Begin by fully disassembling the SM-A910 and removing the motherboard. Disconnect the battery and ensure no power is applied before making any connections. Identify the eMMC ISP test pads using a verified PCB map. Solder thin wire leads or use a dedicated ISP probe clip to the CLK, CMD, DAT0, VCC, VCCQ, and GND pads. Connect the leads to a compatible ISP adapter (such as Easy-Jtag Plus or UFI Box ISP socket). Launch the tool's software, select the SM-A910 or equivalent eMMC profile, apply the correct voltage settings (VCC 3.3V, VCCQ 1.8V), and initiate the desired operation — read, write, or erase. Always verify connection stability before sending any write commands.

Safety Tips Before You Start

Never apply power to the board while soldering ISP connections. Double-check voltage settings in your tool software before powering on — incorrect voltages will permanently damage the eMMC chip. Use flux and fine-tipped soldering equipment to avoid bridging adjacent pads. Keep the work area static-free by using an anti-static mat and wrist strap. Do not interrupt a write or erase operation once started, as this will corrupt the eMMC. Always take a full backup (read) of the eMMC before performing any write or erase operation.

Pin / Test Point Reference

PinDescription
CLKeMMC clock signal line — Exact pad location on SM-A910 PCB unverified; consult board diagram
CMDeMMC command line — Exact pad location on SM-A910 PCB unverified
DAT0eMMC data line 0; primary data path for 1-bit mode — Minimum required data line for ISP operations
DAT1eMMC data line 1; used in 4-bit bus mode — Optional for 1-bit mode; required for faster 4-bit transfers
DAT2eMMC data line 2; used in 4-bit bus mode — Optional
DAT3eMMC data line 3; used in 4-bit bus mode — Optional
VCC3.3V power supply to eMMC chip — Verify with multimeter before connecting ISP tool
VCCQ1.8V I/O voltage for eMMC signal logic — Critical — incorrect voltage damages eMMC permanently
GNDCommon ground reference point — Multiple GND points available on PCB

Tools required: Easy-Jtag Plus with ISP adapter, UFI Box with ISP socket, UMT (Ultimate Multi Tool) with ISP support, Medusa Pro Box, Fine-tip soldering iron, Flux, Anti-static mat and wrist strap, Multimeter

Supported operations: Read Firmware / eMMC Backup, Write Firmware, FRP Erase, Dead Boot Repair, Pattern / PIN Lock Removal, Bootloader Repair, IMEI Repair (where legally permitted)

⚠ Safety note: Use 3.3V VCC and 1.8V VCCQ only. Never interrupt write/erase operations. Incorrect voltage or pad misidentification will permanently destroy the eMMC chip.