Xiaomi Mi 9T (known globally as Redmi K20) has an elegant design with a bezel-less screen and a retractable front camera. However, the glass rear panel, despite its beauty, is one of the most vulnerable elements of the design. Falling from even a small height on asphalt or accidentally hitting a hard object often leads to cracks, chips or complete glass destruction.
Self-replacement of the back cover is not just an aesthetic procedure, but also an important measure of protection for the internal components of the device. Damaged glass can leak moisture, dust and small abrasive particles that will eventually disable the motherboard or battery.
In this guide, we will take a closer look at the process of dismantling a damaged panel and installing a new one. You will learn what tools will be required to work, how to safely disable the plumes and why the main camera module requires special attention when disassembling. Compliance with technology will allow you to restore the tightness of the case and return the smartphone to its original appearance without overpaying for the services of the service center.
Tools and workplace preparation required
Before you start disassembling, you need to organize your workspace, you need a table with good lighting and a clean surface so that small screws don't get lost, you don't recommend working on fuzzy fabrics or carpets, because static electricity can damage electronics, and you need to do everything slowly and carefully, without sudden movements.
To successfully replace, you'll need a specialized toolkit, and even one of them can make it difficult or damage adjacent components, and the main tool to separate the glass and frame will be a thin metal blade or scalpel, which you need to use with utmost care.
- 🔧 A hair dryer or thermophene (thermopistol) for softening factory glue.
- 🛠️ Set of screwdrivers (cross-haired) PH000 and flat) for screw twisting.
- 🧲 Magnetic mat or container with screw sorting cells.
- 🧴 Clay. B-7000 or E-8000 lock-in.
Special attention should be paid to the suction cup, which is necessary to create the initial gap between the glass and the frame after heating. If you do not have a professional suction cup, you can use a quality suction cup for car windows, but it should be small in diameter. Also prepare a plastic card or mediator to widen the gap without scratching metal.
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Before starting work, be sure to turn off the smartphone and remove SIM-This will prevent the device from accidentally turning on and shorting when the tools come into contact with the board.
Dismantling the old back panel
The process of removing a broken lid starts with heating it. The factory glue that locks the glass to the metal frame is very strong and at room temperature is not mechanically resistant. You need to warm up the perimeter of the device evenly. Don't keep the hair dryer at one point for too long so as not to overheat the battery or the display on the back side.
The optimum heating temperature is about 80-90 degrees Celsius. Keep the hot air flow 3-5 cm from the surface for 2-3 minutes. Periodically touch the glass with your finger (carefully not to cut) - it should become hot but not melt. After that quickly, until the glue has cooled, insert the suction cup into the center of the bottom of the lid and pull up, creating tension.
⚠️ Warning: If there are cracks on the glass, use wide tape to seal the entire surface before heating.This will prevent fragments from crumbled and protect your eyes and the internal components of the phone.
When a small gap appears (literally 1-2 mm), carefully insert a thin metal blade or blade. Drive the tool along the perimeter, cutting the adhesive layer. Move smoothly, trying not to go too deep so as not to damage the plumes coming from the side buttons or the bottom module. Exercise special care in the area of the camera module and the fingerprint scanner (if it is integrated into the screen, the risk is less, but caution will not hurt).
Once you've walked around the perimeter, the lid should be easy to remove. If you feel strong resistance, don't pull, warm up the problem area again. Put the panel removed right away in a safe place away from the edge of the table. Now the insides of the smartphone are open to access, and you can move on to a more subtle operation.
Features of working with the camera module and plumes
One of the key design features of the Xiaomi Mi 9T is the location of the main camera. Unlike many other models, here the camera module is attached directly to the back cover or has a very dense layout with it. If you sloppy remove the glass, there is a high risk of damaging the lens or tearing off the focus plume.
In some versions, when lifting the lid, it may appear to be glued to the camera. That's OK. You need to look carefully at the connection. If the camera module is left hanging on the lid, it needs to be very delicately detached from the main board, first removing the protective plastic slat that holds the connectors.
- 📷 Unscrew the screws that fix the metal protection over the camera module.
- 🔌 Carefully bend the main camera plume using a plastic shoulder blade.
- 🧹 Check the lenses for dust that may have been trapped through the cracks.
- 🔍 Make sure that the front camera mechanism is not clamped.
If you change the lid to color or transparent, make sure that the ring around the lens of the main camera (decorative glass) is moved from the old panel or is present on a new one. Often new lids are sold without this element, and it needs to be carefully re-glued from the old glass, after cleaning from the glue residue. Use alcohol or a special cleaner to degrease the surface.
Nuance with the glue on the camera
Cleaning the frame and preparation for gluing
Once the old panel is removed, the metal frame of the case leaves the residue of the factory glue, which must be removed completely. The new cover must fit to a perfectly flat surface, otherwise there will be gaps in the case through which moisture will penetrate. Use a plastic card or nail to clean it so that you do not leave scratches on the aluminum.
Degreasing is a critical step: wipe the perimeter of the frame with a napkin dipped in isopropyl alcohol. Do not use water or aggressive solvents such as acetone, which can damage the paint or plastic frame elements. The surface should be dry, clean and matte to the touch before applying a new adhesive.
If additional elements, such as the brand logo or antenna inserts, have been installed on the old cover, check their integrity.Sometimes the Mi or Redmi logo may unstuck.It also needs to be cleaned and prepared for installation on a new panel.Make sure all speaker and microphone holes are free of glue plugs.
| Preparation phase | Tool. | Implementation time | Importance |
|---|---|---|---|
| Removing old glue | Plastic spatula | 10-15 minutes | Tall. |
| Degreasing | Alcohol + napkin. | 2-3 minutes | Critical |
| Checking the plumes | Visually. | 1 minute | Tall. |
| Tapping the lid | 1 minute | Medium |
Installation of a new cover and fixation
Now you can start the final assembly. Put a thin, uniform layer of B-7000 or E-8000 glue on a metal frame around the perimeter. Don't pour too much glue -- it shouldn't squeeze out into the body when pressed. Just a strip about 1 mm thick. Pay special attention to the corners, because that's where the detachment most often starts.
Carefully align the new cover with the body. Start at the top of the camera module, making sure the holes match. Smoothly lower the glass down. Don't push hard on the center of the cover so you don't crush the display on the back. Easy pressing around the perimeter with your fingers is enough.
☑️ Final assembly
For reliable fixation while the glue is drying, it is recommended to use special clamps for screens or simply wrap the smartphone tightly with stationery rubber bands (at least 5-6 pieces), this will ensure a uniform fit of glass throughout the area. Leave the device alone for at least 30-40 minutes. Complete drying of the glue takes about 24 hours, but it gains primary strength quickly.
⚠️ Warning: Excess glue from under the glass must be removed immediately before it freezes. Use a toothpick or plastic card. Frozen glue is difficult to remove without scratching the glass or frame.
Frequent mistakes and expert advice
When replacing the back cover with the Xiaomi Mi 9T, beginners often make mistakes that can cost the functionality of the device. One of the most common is rush. Trying to remove the cover without sufficient heating or installing a new panel on a dirty frame is guaranteed to lead to problems in the future. It is also dangerous to use metal tools without insulation, which can lead to a closure.
Another important point is that it's tight. You don't expect it to be completely waterproof, like the new one from the factory. The B-7000 glue provides good spray and dust protection, but water immersion is still contraindicated. The quality of gluing depends on the cleanliness of the surfaces and the pressure exposure time.
If you notice that the side buttons (volume and on) are tight or sticky after assembly, then the lid is not flat or the glue layer is too thick, in which case it is better to carefully remove the panel again (a little bit of heating) and redo the work than to use a phone with defective buttons.
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The quality of the adhesive and the time it's polymerized are the main factors of success, so don't skimp on consumables and let the device lie down for the time it needs.