Celkon Astro (Campus A407 Astro) Firmware Flash File Download [Stock Rom]

This page provides the official download links for the Celkon Astro stock ROM. The Celkon Astro (also known as Campus A407 Astro) is an ultra-budget, compact 4-inch smartphone designed for basic communication. If your phone is stuck on the Celkon logo, has been infected with malware that can’t be removed, or is experiencing a bootloop, flashing the stock firmware is the ultimate solution. This package contains the original Android 6.0 Marshmallow software in a .pac file format, designed for installation with the SPD Upgrade Tool on its Spreadtrum chipset.

Reinstalling the firmware will perform a complete wipe, removing all data, screen locks, and viruses. It is the most effective way to unbrick a Celkon Astro and restore it to a clean, factory state. We have listed two firmware versions below; please read the note under the table for guidance on which to choose.

Celkon Astro: Quick Device Specifications

Please confirm these details match your device. This is an entry-level 3G smartphone with very basic hardware.

Device Model:

Celkon Astro (Campus A407 Astro)

Release Date:

Circa 2017

Chipset:

Spreadtrum SC7731C (Quad-core 1.2 GHz)

Display:

4.0 inches, 480 x 800 pixels (WVGA)

Battery:

1400 mAh, Removable Li-Ion

RAM/Storage:

512MB RAM / 4GB Internal Storage

Key Features:

Compact 4-inch Design, 3G Connectivity

Required Downloads for Flashing

You will need the following specific tools and drivers for Spreadtrum devices.

• SPD Upgrade Tool
• Spreadtrum USB Drivers
• A Celkon Astro Firmware Package (choose a version from the table below)

Celkon Astro Firmware Download Links

How to Flash Celkon Astro Firmware (.pac file)

This is a summary of the flashing process using SPD Upgrade Tool. For a more comprehensive guide with screenshots, please visit our detailed pillar article.

1. Preparation: Download your chosen firmware version, the SPD Upgrade Tool, and Spreadtrum drivers. Extract all zip files into a single folder.
2. Driver Installation: Install the Spreadtrum USB drivers on your computer and restart if prompted.
3. Load Firmware: Run UpgradeDownload.exe. Click the first Gear icon (“Load Packet”) and select the .pac firmware file you extracted.
4. Start Flashing: Click the Play button (“Start Downloading”) to put the tool into flashing mode.
5. Connect the Phone: Power off your Celkon Astro completely. Press and hold the Volume Down key. While holding the key, connect the phone to your PC via a USB cable.
6. Completion: The tool should detect the phone and begin flashing. You can release the volume key once the progress bar appears. A green “Passed” message will indicate the process is complete. Disconnect the phone and power it on.

For in-depth instructions and troubleshooting for the SPD Upgrade Tool, please visit our complete guide: How to Use the SPD Upgrade Tool to Flash Your Smartphone.

Troubleshooting Common Issues

Here are some specific issues you might encounter with the Celkon Astro.

1. Extremely Slow Performance (Unusable Lag)

Cause: This phone’s primary limitation is its hardware, specifically the 512MB of RAM. Android 6.0 Marshmallow and even basic apps can struggle to run smoothly on such limited memory.

Solution: A full firmware flash will restore the phone to its “best-case” performance by removing all junk files and user data. After flashing, do not install any additional apps if possible. If you must, only use the absolute lightest apps available (e.g., Opera Mini for browsing). This device is not suitable for social media or modern apps.

2. SPD Upgrade Tool Error: “Failed: Uart send error”

Cause: This is a very common error with the SPD tool that indicates a problem with the driver or USB connection. The tool is failing to establish a stable communication link with the phone.

Solution: Ensure the Spreadtrum drivers are properly installed (reinstall them and restart your PC). Use a high-quality USB cable and connect directly to a main USB port on your computer, not a hub. Finally, make sure you press and hold the boot key (Volume Down) *before* plugging in the cable.

3. Phone is Infected with Malware or Adware

Cause: Ultra-budget phones are often targeted by malicious software that can be difficult to remove.

Solution: Flashing the stock .pac firmware is the only guaranteed way to remove deep-level infections. The process completely reformats the phone’s storage, wiping out any malicious code and replacing it with a clean system.

Frequently Asked Questions (FAQs)

Which of the two firmware versions should I use?

We recommend you start with the file that has the latest build date, which is V06 from October 2016. If that version does not work for your specific device, the next logical choice is the file with the highest version number, V10 from September 2016.

Can I install WhatsApp on the Celkon Astro?

While you might be able to install an older version, it is not recommended. With only 512MB of RAM, the app will run extremely poorly, likely crashing or freezing constantly. The phone is not powerful enough for modern messaging apps.

Does this phone support 4G?

No. The Spreadtrum SC7731C chipset in the Celkon Astro is a 3G-only processor. It does not have the hardware to connect to 4G LTE networks.

Will this firmware remove a forgotten password or pattern lock?

Yes. The flashing process erases all user data on the phone, which includes any screen lock security like PINs, passwords, or patterns. Your phone will be completely reset.

Conclusion

Restoring the official stock firmware on your Celkon Astro is the ultimate solution for fixing critical software problems, from bootloops to stubborn malware. This guide provides all the available firmware files and a reliable flashing method to get your compact device back into a usable state. Given the device’s very limited hardware, this process is ideal for restoring it for basic calling and offline tasks.

If this guide helped you, please share your experience in the comments, especially which firmware version worked for you. Your feedback helps our community!