How to Fix No OS Found Error on TWRP?

If you’re an Android device user who is venturing into the world of custom development or trying to flash external stock firmware, you may encounter the common issue of the “No OS Found” error in TWRP (TeamWin Recovery Project) recovery. This error occurs when you’re attempting to flash a new firmware file via TWRP, and the recovery program fails to detect the installed system. In this comprehensive guide, we will explore various solutions to fix this error and get your device up and running smoothly.

Before we dive into the solutions, let’s understand why this error occurs. When flashing a new firmware file via TWRP, it is recommended to wipe out various device partitions, including Data, Dalvik, System, Boot, Vendor, etc. However, only erasing the system partition might not always resolve the issue. The error message indicates a boot partition problem, which prevents the recovery program from detecting the installed system.

Solutions to Fix the No OS Found Error in TWRP

1. Change Slots (For A/B Devices)

If your device has a dual partition option (A/B devices), you can try switching to the active slot. The inactive slot does not have the system.img file installed, which can result in the “No OS Found” error. Follow these steps to change slots:

1. Go to the Reboot option in TWRP and check the current slot (A/B).
2. If the current slot is A, tap on the Slot B button or select B if the current slot is A.
3. You will see the “No OS” error message again, but you can skip it by performing a right swipe.
4. Your device will now boot to the other slot. Go to Reboot and select System.
5. If your device successfully boots to the OS, the error has been resolved.

If you’re still facing the same error, proceed to the next method.

2. Restore Nandroid Backup

If you have previously created a Nandroid backup before encountering the “No OS Found” error, you can easily restore the backup file using TWRP. Here’s how:

1. Go to the Restore option in TWRP.
2. Select your Nandroid backup file.
3. Perform a right swipe to restore the backup.
4. Once the restoration is complete, go to Reboot and select System.
5. Your device should now boot to the OS.

Restoring a Nandroid backup can be a reliable solution if you have a backup available.

3. Use MTP

Mounting your device’s storage via TWRP and transferring the firmware zip file directly onto your device can help resolve the “No OS Found” error. Follow these steps:

1. Connect your device to your PC via a USB cable.
2. Go to the Mount option in TWRP and checkmark the Data partition.
3. Tap on the Enable MTP button at the bottom right corner.
4. Your device will appear on your PC. Transfer the firmware zip file to your device.
5. Flash the ROM file according to the instructions provided by the ROM developer or on the XDA Developers blog.
6. If no specific instructions are available, go to Wipe in TWRP and select Data, System, and Cache partitions one by one. Perform a right swipe to wipe those partitions.
7. Go to Install, select the ROM ZIP file, and perform a right swipe to flash it.
8. After the installation is complete, boot to the newly installed OS via Reboot and select System.

Using MTP can help ensure a successful installation of the firmware file and resolve the error.

4. Use ADB Sideload

In some cases, the data partition may be encrypted, making it difficult to identify conflicting files. Using ADB sideload can provide a solution. Here’s how to do it:

1. Download and extract the Android SDK Platform Tools on your PC.
2. Transfer your ROM file to the platform-tools folder.
3. Go to Advanced in TWRP and select ADB Sideload.
4. Perform a right swipe to start the sideload process.
5. Connect your device to your PC via a USB cable.
6. Open Command Prompt on your PC by typing “cmd” in the platform-tools folder’s address bar and hitting Enter.
7. Enter the following command to flash the file via sideloading (replace “file.zip” with the actual file name): adb sideload file.zip
8. Go to the Reboot section in TWRP and select System.
9. If your device successfully boots to the system, the “No OS Found” error has been resolved.

5. Flash Stock Firmware

If none of the above methods work, flashing the stock firmware via Fastboot Commands or device-specific tools like SP Flash Tool, Mi Flash Tool, or Android Flash Tool may be necessary. Follow these steps:

1. Go to Reboot in TWRP and select Bootloader.
2. Skip the “No OS” error message and perform a right swipe to confirm.
3. Your device will boot into Fastboot Mode.
4. Flash the Stock Firmware using Fastboot Commands specific to your device’s OEM or model number.
5. Follow the instructions carefully and patiently to boot your device into the newly installed OS.

Flashing the stock firmware can provide a fresh start and resolve any underlying issues causing the “No OS Found” error.

Conclusion

Encountering the “No OS Found” error in TWRP recovery can be frustrating, but with the right solutions, you can resolve this issue and get your device back up and running smoothly. We have provided several methods, including changing slots, restoring Nandroid backups, using MTP, utilizing ADB sideload, and flashing stock firmware. Try these solutions one by one until you find the one that works for your device. Remember to follow the instructions carefully and back up your data before attempting any modifications.

Experiencing difficulties with your Device, check out our “How To” page on how to resolve some of these issues.