ZTE Optus X Vista Z6621O Firmware Flash File Download [Stock Rom]
The Optus X Vista (model Z6621O) is a modern, budget-friendly smartphone from the Australian carrier Optus, offering a large display and Android 11. For users experiencing issues like being stuck in a bootloop, dealing with software glitches, or needing to recover a non-responsive device, flashing the official stock firmware is the most reliable solution.
Important Note: This device is powered by a UNISOC SC9863A chipset. The restoration process requires the SPD Upgrade Tool and the firmware in .pac format. This will restore the official Optus Australia software, including all pre-installed applications and the original network lock.
Quick Device Specs
- Device: Optus X Vista (Z6621O)
- Release year: 2021
- Chipset: UNISOC SC9863A
- Display: 6.52″ HD+ IPS LCD
- Battery: 4000 mAh (Non-removable)
- Memory: 3GB RAM + 32GB storage
- Camera: 16MP + 2MP dual rear, 5MP front
- OS: Android 11
- Carrier: Optus (Australia)
Required Downloads
| File / Tool | Download Link |
|---|---|
| SPD Upgrade Tool | Download Tool |
| SPD/UNISOC USB Drivers | Download Drivers |
Stock ROM & Firmware
| Version | Android | Carrier | Type | Download | Size |
|---|---|---|---|---|---|
| V1.0.0B19 | 11 | Optus (Australia) | SPD / PAC | Download | ~1.6 GB |
Quick Flashing Guide
- Download and install the SPD USB Drivers and the SPD Upgrade Tool on your computer.
- Extract the downloaded firmware ZIP file to get the firmware package with a .pac extension.
- Launch the SPD Upgrade Tool, click the gear icon to “Load Packet,” and select the .pac file.
- Power off your phone, then press and hold the Volume Down button while connecting it to your PC to begin the flashing process.
For a complete, step-by-step tutorial with screenshots, please refer to our definitive guide:
How to Flash Firmware with the SPD Upgrade Tool
FAQs
Q1. Will this firmware remove the Optus network lock?
No. This is the official Optus stock firmware. It will restore the phone to its original software, including the network lock. The device will only work with an Optus SIM card in Australia.
Q2. What is a .pac file and why is it used?
A .pac file is a compressed firmware package for devices with UNISOC (formerly Spreadtrum) chipsets. It contains all the phone’s software partitions (system, boot, etc.) in a single file, which allows the SPD Upgrade Tool to flash the entire system at once.
Q3. The SPD Upgrade Tool is stuck on “Checking Baudrate”. What does that mean?
This is a common connection error. It indicates the tool cannot communicate with the phone’s chipset. The primary causes are improperly installed drivers, a faulty USB cable, or not holding the correct boot key (Volume Down) when connecting the device.
Q4. My computer is not detecting the phone at all. What should I do?
This is almost always a driver issue. Ensure you have installed the SPD drivers correctly. On modern versions of Windows, you may need to disable Driver Signature Enforcement. Also, try using a different USB port (USB 2.0 is often more reliable) and a different cable.
Troubleshooting (Optus X Vista)
- “Invalid SIM” error: This message is expected if you are using a SIM card from a carrier other than Optus. The phone is network-locked to Optus Australia.
- Flashing Fails or Stops Midway: This can be caused by a loose USB connection or a corrupted .pac file. Ensure the cable is secure throughout the process. If it fails again, try re-downloading the firmware file.
- Optus apps are crashing or not working: After a fresh flash and setup, connect to Wi-Fi and open the Google Play Store. Go to “My apps & games” and update all installed applications.
- Device is stuck on the Optus logo after flashing: The first boot can take 10-15 minutes. If it is still stuck after that time, you will need to boot into recovery mode (usually by holding Volume Up + Power from an off state) and perform a “Wipe data/factory reset”.
