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UZ801 Pinouts: EDL 9008 Test Points, 1.8V UART & GPIO Map (V3.0 / V3.31)

The UZ801 is favored by hardware hackers because its test pads are clearly exposed on the bottom side of the PCB, allowing easy recovery without having to solder underneath RF metal shields.

PCB Layout & Test Point Map

Section titled “PCB Layout & Test Point Map”

Bottom Side (Back of PCB)

Section titled “Bottom Side (Back of PCB)”
   ┌─────────────────────────────────────────────────────────┐
   │ [USB-A]                                                 │
   │                                                         │
   │            ( ) EDL (TP1)                                │
   │                                                         │
   │            ( ) TX (1.8V)                                │
   │            ( ) RX (1.8V)                                │
   │            ( ) GND                                      │
   │                                                         │
   │                      ┌────────────────────────┐         │
   │                      │ Micro-SIM Tray         │         │
   │                      │                        │         │
   │   [Antenna IPEX]     └────────────────────────┘         │
   └─────────────────────────────────────────────────────────┘

1. Entering EDL Recovery Mode (Qualcomm 9008)

Section titled “1. Entering EDL Recovery Mode (Qualcomm 9008)”

When the bootloader is erased or the kernel panics on boot, Qualcomm’s Emergency Download Mode (EDL) is your unbrick recovery path.

Step-by-Step Procedure:

Section titled “Step-by-Step Procedure:”
  1. Disconnect the UZ801 from all USB ports and power sources.
  2. Using metal tweezers, conductive wire, or a bent paperclip:
    • Connect the gold test pad marked EDL (or TP1) to GND (or the metal frame of the USB connector).
  3. While maintaining the short, plug the UZ801 into your computer’s USB port.
  4. Keep the short connected for 2 seconds, then release.
  5. Check your host computer:
    • Linux: Run lsusb. Look for 05c6:9008 Qualcomm, Inc. Gobi Wireless Modem (QDL mode).
    • Windows: Device Manager will list Qualcomm HS-USB QDLoader 9008 under Ports (COM & LPT).

2. Hardware UART Serial Console (1.8V Logic)

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

The UZ801 routes the SoC’s primary hardware serial console directly to dedicated test pads.

Pin Connections

Section titled “Pin Connections”
UZ801 Pad Direction USB-to-UART Adapter Pin
TX Output RX (Receive on PC)
RX Input TX (Transmit from PC)
GND Ground GND (Common Ground)

Serial Terminal Settings:

Section titled “Serial Terminal Settings:”
  • Baud Rate: 115200
  • Data Bits: 8
  • Parity: None
  • Stop Bits: 1
  • Flow Control: None
Terminal window
# Example picocom connection
picocom -b 115200 /dev/ttyUSB0

3. GPIO Pin Assignments & LEDs

Section titled “3. GPIO Pin Assignments & LEDs”

The UZ801 features three onboard indicator LEDs driven directly by PMIC/SoC GPIOs:

Function Hardware GPIO Active State Notes
Power / System LED GPIO 0 Active High Controlled by systemd / Linux trigger
Wi-Fi Status LED GPIO 1 Active High Linked to phy0-rx/tx in network configs
4G Cellular LED GPIO 2 Active High Blinks during cellular registration
SIM Detect Switch GPIO 50 Pull-up High when SIM is inserted

4. RF Antenna Modification Pads

Section titled “4. RF Antenna Modification Pads”

Near the edge of the board, an unpopulated Murata MS-156 / SWD RF switch footprint allows soldering an IPEX/u.FL connector:

  • Center pin: Connect to the RF signal feed trace.
  • Flank pads: Solder to the ground copper flood plane.
  • Adding an external 4G paddle antenna improves reception by +15 to +20 dBm in fringe cellular coverage areas.

Frequently Asked Questions — UZ801

How do I flash OpenStick Debian Linux onto a UZ801 4G USB modem?

Download the automated 1-Click OpenStick Installer (openstick-installer.zip) for Windows, macOS, or Linux. It backs up your factory eMMC partitions, preserves your IMEI/QCN cellular calibration, and flashes OpenStick Debian automatically.

Which UZ801 PCB silkscreen revisions are supported by OpenStick?

Genuine Qualcomm MSM8916 boards marked UZ801_V2.1, UZ801_V2.2, UZ801_V3.0, and UZ801_V3.31 with 4GB BGA eMMC storage have full first-class support.

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