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UF896 & Zhihe NAND Pinouts: Clock Shorting Method & UART

Because many Zhihe and UF896 boards lack clearly labeled EDL test pads, entering Qualcomm 9008 Emergency Download Mode often requires a specialized technique: shorting the SPI-NAND clock line.

PCB Layout & Component Map

Section titled “PCB Layout & Component Map”

Top / Component Side

Section titled “Top / Component Side”
   ┌─────────────────────────────────────────────────────────┐
   │ [USB-A]                                                 │
   │                                                         │
   │   [TX] [RX] [GND] (1.8V UART)                           │
   │                                                         │
   │        ┌─────────────────────────┐                      │
   │        │     MSM8916 SoC         │                      │
   │        │     (under shield)      │     ┌─────────┐      │
   │        └─────────────────────────┘     │  NAND   │      │
   │                                        │  Flash  │      │
   │        ┌─────────────────────────┐     └─────────┘      │
   │        │     Micro-SIM Tray      │     (SOP-8/TSOP)     │
   │        │                         │                      │
   │        └─────────────────────────┘                      │
   │                                                         │
   │   [Antenna Trace]                                       │
   └─────────────────────────────────────────────────────────┘

1. Entering Qualcomm EDL Mode (The NAND CLK Short Method)

Section titled “1. Entering Qualcomm EDL Mode (The NAND CLK Short Method)”

When a NAND board is soft-bricked and has no labeled EDL test pads:

Why this method works:

Section titled “Why this method works:”

When the MSM8916 powers on, its internal ROM bootloader attempts to communicate with the NAND flash over SPI/QSPI. If the clock (CLK) or data line (MISO/MOSI) is grounded during this initial handshake, the hardware read fails. The ROM bootloader interprets this as total flash failure and automatically falls back to Qualcomm Emergency Download Mode (EDL 9008).

Step-by-Step Procedure:

Section titled “Step-by-Step Procedure:”
  1. Disconnect the stick from USB power.
  2. Locate the 8-pin SOP-8 SPI NAND chip (e.g. GigaDevice GD5F or Winbond 25N):
    • Pin 6 is typically the Clock (CLK) line.
    • Pin 4 is Ground (GND).
  3. Take a pair of metal tweezers and gently short Pin 6 (CLK) to Pin 4 (GND) (or short Pin 6 to the metal USB outer casing).
  4. While holding the short, plug the stick into your PC’s USB port.
  5. After 1 to 2 seconds, release the tweezers.
  6. Check your host computer:
    Terminal window
    lsusb | grep 05c6:9008
    # Qualcomm, Inc. Gobi Wireless Modem (QDL mode)

2. Hardware UART Serial Console (1.8V Logic)

Section titled “2. Hardware UART Serial Console (1.8V Logic)”

The Zhihe/UF896 boards expose standard Snapdragon 410 serial pins:

  • TX: Connects to USB adapter RX (1.8V)
  • RX: Connects to USB adapter TX (1.8V)
  • GND: Connects to adapter GND
  • Baud Rate: 115200 (8N1)

Frequently Asked Questions — UF896 / Zhihe NAND

Why do UF896, Zhihe NAND, and ASR1802 sticks fail to boot OpenStick Debian?

UF896 and Zhihe NAND clones replace eMMC storage with tiny SPI-NAND flash (256MB/512MB), while ASR1802 and ZX297520 dongles use non-Qualcomm CPUs. Always buy verified eMMC MSM8916 boards such as UZ801 or UFI003.

👉 Ready to flash? Download the 1-Click OpenStick Debian Installer or browse Verified Store Links.