Vivo Y31 5G ISP PinOUT | Test Points (Hardware-Level Access)
The Vivo Y31 5G ISP PinOUT provides direct access to the phone’s onboard memory (EMMC) while it remains soldered on the motherboard — no need to desolder the chip. This is incredibly useful for dead boot repair, FRP bypass, data recovery, partition repair, and low-level firmware flashing using ISP-enabled tools such as UFI Box, Easy JTAG, Flash64 Box, Hydra Tool, or similar repair interfaces.
What Is ISP (In-System Programming)?
ISP — In-System Programming refers to a set of contact points on the mainboard that let you communicate directly with the internal storage chip (EMMC/UFS) without physically removing it. ISP allows you to:
Recover data from dead devices
Bypass FRP locks
Fix “Unknown USB” or EDL detection issues
Restore partitions or boot sectors
Flash firmware at a low level using supported tools
This method is often used when the phone does not respond to standard recovery modes, fastboot, ADB, or normal flashing processes.
Where Are the ISP Test Points Located on Vivo Y31 5G?
For Vivo Y31 5G (model V2521 / V2521Li), the ISP test points are near the EMMC chip on the motherboard, usually under the metal shield or near the main processor. These pads are small metallic contact points, grouped around other test points.
The key ISP connection points you will usually find are:
🔹 CLK – Clock signal for EMMC/ISP
🔹 CMD – Command line for EMMC interface
🔹 DAT0 – Data line 0 (used for ISP communication)
🔹 VCC / VCCQ – Power supply reference
🔹 GND – Ground common reference
Note: On Vivo Y31 5G, only essential lines for EMMC ISP are typically exposed (CLK, CMD, DAT0, GND and supply references).
Typical ISP PinOUT Signal Definitions
| Test Point Name | Function |
|---|---|
| CLK | EMMC clock signal (timing reference) |
| CMD | EMMC command interface |
| DAT0 | Primary data line for EMMC |
| VCC / VCCQ | Power supply lines for storage interface |
| GND | Ground common reference |
👉 These are the core ISP signals needed for most tool connections when performing low-level actions with the phone.
Tools Compatible With ISP Connections
When working with Vivo Y31 5G ISP points, compatible hardware tools include:
✔ UFI Box
✔ Easy JTAG Plus
✔ Flash64 Box
✔ Hydra Tool
✔ Medusa Pro (for EMMC)
These boxes support EMMC ISP interfaces and can communicate directly with the storage chip when properly connected to test points.
How to Physically Connect ISP Test Points
📍 Important: Before soldering or connecting anything:
Disconnect the battery — this avoids short circuits or voltage conflicts
Clean the board with 99% isopropyl alcohol to remove flux or dirt.
Common ISP Use-Cases for Vivo Y31 5G
Technicians use ISP pinouts for situations such as:
🔹 Dead Boot Recovery – When the phone does not boot normally at all.
🔹 FRP Bypass – When Factory Reset Protection blocks access.
🔹 Unknown USB Device Problem – When the PC cannot recognize the device.
🔹 Partition Repair / Firmware Restore – Fixing corrupted storage areas.
🔹 Data Recovery – Extracting user data from a non-booting device.
Tips for Safe ISP Work
✔ Use microscope or magnifier to locate tiny test points correctly.
✔ Keep your bench organized and ESD protected.
✔ Always verify each signal before connection (especially GND).
✔ Re-check tool configuration for Vivo Y31 5G before running operations.