On the Nokia X1-01 motherboard, the system connector is located at the bottom of the device. If you remove the battery and the back cover, you are looking at the external interface. However, the data pins are often routed internally or require soldering jumper wires to specific test points on the PCB.
| Pin Name | Function | Description | | :--- | :--- | :--- | | | Power Input (+5V) | Provides charging voltage from the USB source. | | GND | Ground | The negative terminal; the return path for current. | | D+ | Data Plus | The positive data line for USB communication. | | D- | Data Minus | The negative data line for USB communication. | | BSI | Battery Size Indicator | Used for battery identification and safety. | | MCU | Flashing Data | Used for low-level flashing via ATF/JAF boxes. | nokia x1-01 usb pinout
However, one of the most confusing aspects of this device today—especially for repair technicians, vintage phone enthusiasts, or users trying to recover old data—is its charging and data port. Unlike modern micro-USB or USB-C ports, the Nokia X1-01 uses a (often referred to as the "Nokia Barrel Jack" or "Pin Connector"). This port looks like a small, round barrel, but it is capable of both charging and, crucially, USB data transfer. On the Nokia X1-01 motherboard, the system connector
Unlike modern phones that simply enumerate USB, the Nokia X1-01 (and similar S30/S40 devices) uses a detection mechanism. The phone senses the resistance between D+ and D- to determine what type of accessory is connected. | Pin Name | Function | Description |
The service pads are located directly under the battery terminal on the phone's printed circuit board (PCB). Below is the exact pinout mapping required to construct a data cable or interface with flashing hardware. Hardware Test Points Mapping Pin Number Signal Name Description Connection Point (USB / Interface) VBAT Battery Positive Power Connected to Power VCC (+3.7V / +5V via resistor) Pin 2 GND Ground Reference Connected to USB Ground / Shield Pin 3 TX / FBUS_TX Transmit Data Connected to Interface Receiver (RX) Pin 4 RX / FBUS_RX Receive Data Connected to Interface Transmitter (TX) Pin 5 BSI Battery Size Indicator Connected to GND via a 3.3kΩ to 7.5kΩ resistor Pin 6 VPP Flash Programming Voltage Usually left disconnected during standard USB modification 🛠️ DIY USB-to-FBUS Cable Modification