The ZTE Blade A7S 2020 (model A7020) is an entry-level smartphone designed to handle everyday tasks with its large display and capable triple-camera system. It is powered by a UNISOC (formerly Spreadtrum) SC9863A chipset, making it a reliable choice for the budget-conscious user. If your device is stuck in a bootloop, infected with malware, or you simply want to restore it to its original factory condition, flashing the official stock ROM is the most effective solution. This guide provides the official firmware for the Telcel Mexico variant and a clear, step-by-step flashing guide using the SPD Upgrade Tool.
Important: This firmware is specifically for the ZTE Blade A7S 2020 (A7020, Telcel Mexico variant). Flashing this file on a different model or regional variant may cause your device to brick. The flashing process for UNISOC/Spreadtrum devices is different and requires specific tools.
Quick Device Specs
- Device: ZTE Blade A7S 2020 (A7020)
- Release year: 2020
- Chipset: UNISOC SC9863A
- Display: 6.5″ IPS LCD, HD+
- Battery: 4000 mAh
- Original OS: Android 10
Required Downloads
To flash a Spreadtrum/UNISOC device, you will need the specific drivers and flashing tool listed below.
| File / Tool | Download Link |
|---|---|
| SPD Upgrade Tool | Download Latest Version |
| Spreadtrum/UNISOC USB Drivers | Download Drivers |
Stock ROM (Firmware)
| Region / Carrier | Build | Android | Type | Download | Chipset |
|---|---|---|---|---|---|
| Mexico (Telcel) | V1.6 | 10 | SPD .pac Firmware | Download | UNISOC/SPD |
How to Flash (SPD Upgrade Tool)
This method is for restoring the official stock firmware and will erase all data on your device.
- Install Drivers: Download and extract the Spreadtrum/UNISOC USB Drivers. Run the installer. You may need to disable Driver Signature Enforcement in Windows for the drivers to install correctly.
- Extract Tools & Firmware: Extract the SPD Upgrade Tool and the downloaded firmware .zip file into separate folders on your desktop.
- Launch the Tool: Open the SPD Upgrade Tool folder and run UpgradeDownload.exe as an administrator.
- Load Firmware: Click the first Gear icon (Load Packet). Navigate to the extracted firmware folder and select the large .pac file. It may take a minute to load.
- Start Flashing Process: Click the Play icon (Start Downloading). The status will show “Waiting”.
- Connect Your Phone: Power off your ZTE Blade A7S 2020 completely. Now, press and hold the Volume Down button, and while holding it, connect the phone to your PC with a USB cable.
- Begin Flashing: The tool will detect the phone, and the flashing process will begin. You can release the Volume Down button once the progress bar starts moving.
- Finish: The process will take several minutes. Once it’s finished, you will see a green “Passed” message. You can now disconnect your phone and power it on. The first boot will take longer than usual.
Device-Specific Troubleshooting for Spreadtrum / UNISOC Flashing
Flashing SPD/UNISOC devices has its own unique challenges. Here are the most common ones:
- Driver Installation is Key: The most frequent issue is the PC not detecting the phone. You must install the Spreadtrum drivers correctly. On Windows 10/11, this often requires disabling ‘Driver Signature Enforcement’ before installation. When connected correctly in flashing mode, your device should appear as ‘SPRD U2S Diag’ or similar in the Windows Device Manager.
- Using the Correct “Boot Key”:** To initiate the flash, you need to hold down the correct boot key while connecting the phone. For most ZTE Spreadtrum devices, this is the Volume Down button. If that doesn’t work, try holding both Volume Up and Volume Down buttons together.
- Tool Stuck on “Checking Baudrate”:** If the tool gets stuck on this step and then fails, it indicates a communication problem. The most common causes are faulty drivers, a bad USB cable, or an incompatible USB port. Always use a high-quality USB cable and try a different port on your computer (USB 2.0 often works best).
- Unpacking the Firmware: Remember that the firmware you download is a .zip archive. You must extract it first to find the .pac file inside. The .pac file is what you load into the SPD Upgrade Tool, not the .zip file.
FAQs
Q1. What is a .pac file? A .pac file is a packed firmware file used for Spreadtrum/UNISOC chipsets. It contains all the necessary partitions—system, boot, recovery, modem, etc.—in a single, integrated file for flashing with tools like the SPD Upgrade Tool.
Q2. Can I use Mi Flash Tool or SP Flash Tool for this device? No. Those tools are for Qualcomm and MediaTek devices, respectively. The ZTE Blade A7S 2020 uses a UNISOC/Spreadtrum chipset and requires the specific SPD Upgrade Tool or Research Tool.
Q3. Will this firmware remove my carrier (Telcel) lock? No. Flashing official stock firmware will restore the phone’s software, but it will not remove a network or SIM lock that has been applied by the carrier.
