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Introduction

Use this guide to replace the back cover on your Samsung Galaxy S21 Ultra.

Before you begin, refer to the Samsung Self-Repair document for safety information.

Note: Retaining water resistance after the repair will depend on how well you reapply the adhesive, but your device will lose its IP (Ingress Protection) rating.

  1. Samsung Galaxy S21 Ultra Back Cover Replacement, Heat the back cover: step 1, image 1 of 1
    • Unplug and power off your phone before you begin.

    • Prepare an iOpener and apply it to the back cover for at least three minutes to loosen the adhesive underneath.

    • A hair dryer, heat gun, or hot plate may also be used, but be careful not to overheat the phone—the display and internal battery are both susceptible to heat damage.

  2. Samsung Galaxy S21 Ultra Back Cover Replacement, Insert an opening pick: step 2, image 1 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement, Insert an opening pick: step 2, image 2 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement, Insert an opening pick: step 2, image 3 of 3
    • Secure a suction handle to the bottom edge of the back cover, as close to the edge as possible.

    • If the back cover is badly cracked, covering it with a layer of clear packing tape may allow the suction cup to adhere. Alternatively, very strong tape may be used instead of the suction cup. If all else fails, you can superglue the suction cup to the broken cover.

    • Lift the back cover with the suction handle to create a small gap between the back cover and the frame.

    • If you have trouble creating a gap, apply more heat to further soften the adhesive. Follow the iOpener instructions to avoid overheating.

    • Insert an opening pick into the gap you created.

    • Slide the opening pick to the bottom left corner to slice the adhesive.

    • Leave the opening pick in place to prevent the adhesive from resealing.

  3. Samsung Galaxy S21 Ultra Back Cover Replacement, Slice the adhesive: step 3, image 1 of 2 Samsung Galaxy S21 Ultra Back Cover Replacement, Slice the adhesive: step 3, image 2 of 2
    • Insert a second opening pick at the bottom edge of your phone.

    • Slide the opening pick to the bottom right corner to slice the adhesive.

    • Leave the opening picks in place to prevent the adhesive from resealing.

  4. Samsung Galaxy S21 Ultra Back Cover Replacement: step 4, image 1 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement: step 4, image 2 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement: step 4, image 3 of 3
    • If the adhesive becomes hard to cut, it has most likely cooled down. Use your iOpener for two to three minutes to reheat it.

    • Insert a third opening pick at the bottom right corner of your phone.

    • Slide the opening pick along the right edge of your phone to slice the adhesive.

    • Leave the opening pick in the top right corner to prevent the adhesive from resealing.

  5. Samsung Galaxy S21 Ultra Back Cover Replacement: step 5, image 1 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement: step 5, image 2 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement: step 5, image 3 of 3
    • When you slice near the camera assembly, insert only the tip of the opening pick (~ 4-5 mm) to avoid damaging or smearing the camera.

    • Insert a fourth opening pick underneath the top right corner of your phone.

    • Slide the opening pick along the top edge to slice the adhesive.

    • Leave the opening pick in the top left corner to prevent the adhesive from resealing.

  6. Samsung Galaxy S21 Ultra Back Cover Replacement: step 6, image 1 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement: step 6, image 2 of 3 Samsung Galaxy S21 Ultra Back Cover Replacement: step 6, image 3 of 3
    • Insert a fifth opening pick underneath the top left corner.

    • Slide the opening pick along the left edge of the back cover to slice the remaining adhesive.

    • When you slice near the power button, insert only the tip of the opening pick (~ 3-4 mm) to avoid damaging the power and volume button flex cable.

  7. Samsung Galaxy S21 Ultra Back Cover Replacement, Remove the back cover: step 7, image 1 of 2 Samsung Galaxy S21 Ultra Back Cover Replacement, Remove the back cover: step 7, image 2 of 2
    • Remove the back cover.

    • During reassembly:

    • This is a good point to power on your phone and test all functions before sealing it up. Be sure to power your phone back down completely before you continue working.

    • Remove any adhesive chunks with a pair of tweezers or your fingers. Apply heat if you're having trouble separating the adhesive.

    • If you're using Samsung custom-cut adhesives, follow this guide.

    • If you're using double-sided tape, follow this guide.

Conclusion

Compare your new replacement part to the original part—be sure to transfer remaining components and remove adhesive backings from the new part before installing.

To reassemble your device, follow the instructions in reverse order and perform the opposite actions, e.g., "reattach" instead of "removing." Skip steps that use heating and prying, and pay close attention to the 📌 bullets as you work through the steps.

After you've completed the repair, download the Samsung Members App from the Galaxy Store or the Play Store, and follow the Samsung Self-Repair document (beginning page 9) to make sure your device is fully functional.

Take your e-waste to an R2 or e-Stewards certified recycler.

Repair didn’t go as planned? Try some basic troubleshooting, or ask our Answers community for help.

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