Facing issues like bootloop, system crash, or a missing IMEI on your Xiaomi 15 Ultra? You’re not alone. Problems can occur after a failed update, corrupted firmware, or third-party modifications. The good news? You can fix these problems yourself by flashing the right stock firmware and using the correct tools.
In this article, you’ll learn how to flash the Xiaomi 15 Ultra, repair its IMEI, and restore full functionality—just like it came out of the box.
Stock firmware (also known as the ROM or flash file) is the official operating system installed by Xiaomi. It ensures your device works correctly, including hardware communication, security patches, and UI.
When your Xiaomi 15 Ultra becomes unstable, stuck on the logo, or bricked, flashing stock firmware can bring it back to life.
Use stock firmware flashing when:
Prepare these tools and files before you start:
✅ Correct firmware for Xiaomi 15 Ultra (Global, China, or EU version)
✅ Xiaomi USB Drivers
✅ Mi Flash Tool (Fastboot version)
✅ Unlocked bootloader (required for flashing)
✅ Working Windows PC and USB cable
✅ Backup of all important data
Note: Bootloader unlock is mandatory on newer Xiaomi flagships like the 15 Ultra. You’ll need to apply for unlock via Xiaomi’s official unlock tool.
Let’s walk through the full process to flash your Xiaomi 15 Ultra using Fastboot ROM.
.tgz..tgz firmware file.Congratulations! Your phone is now running official stock firmware again.
If you see “Invalid IMEI”, “No service”, or your SIM isn’t detected after flashing, your phone’s IMEI may be corrupted.
Legal Warning: IMEI repair is only allowed on your original device and must match the official IMEI printed on the box.
Since the Xiaomi 15 Ultra uses a Qualcomm Snapdragon processor, use this method:
Some advanced methods involve using:
These tools require a license/dongle and are used by professional repair technicians. They can safely rewrite IMEI using EDL mode (Emergency Download Mode).
Using the wrong firmware may brick your device or permanently disable features like the camera, 5G, or fingerprint sensor.
| Problem | Solution |
|---|---|
| Phone not detected by PC | Reinstall USB drivers or try a new cable |
| Mi Flash error or stuck | Use another firmware version |
| Bootloop after flashing | Wipe data from stock recovery |
| Invalid IMEI after flashing | Use QCN or DIAG tools to restore IMEI |
| Fastboot fails or error | Unlock bootloader again or reinstall Mi Tool |
Flashing firmware on the Xiaomi 15 Ultra is a powerful way to fix serious software problems and restore your phone to factory condition. Whether you’re unbricking your device, removing a bootloop, or repairing IMEI, this guide has you covered.
Just remember:
With care and the right tools, your Xiaomi 15 Ultra can be as smooth and powerful as it was on day one.