Smartphone Xiaomi Mi 8, released in 2018, became one of the first flagships of the company with the AMOLED-screen and support for dual-band GPS, But even the top-end devices are not spared, and owners often face the need to replace a battery that loses capacity over time, or repair a broken display. However, unlike many modern gadgets, the Xiaomi Mi 8 has a design feature: the back glass panel is glued around the perimeter and is not removed by a simple shift, which makes the opening process risky for the inexperienced user.
Before you start dismantling, you need to be clear that breaking the sealed body automatically deprives you of warranty if it was still in effect. The main challenge is that the glue that holds the glass over time polymerizes and becomes very durable, requiring careful heating and the use of special tools to avoid splitting the fragile rear window. In this article, we will discuss in detail how to properly prepare the device, what tools will be needed and what sequence of actions to safely access the internal components.
It is also worth noting that inside the case there is a complex system of plumes and connectors, careless handling of which can lead to failure of the motherboard or camera modules. Incorrect opening often ends in cracks in the glass or damage to thin wiring, so it is important to follow the instructions Step-by-step, not skipping the preparation stages and not neglecting precautions. If you are not sure of your abilities, it is better to contact the service center, but if the decision is made, be patient and the necessary tools.
Tools and workplace preparation required
To successfully perform the task of opening Xiaomi Mi 8 conventional set of screwdrivers will not be enough, as the key factor here is the work with the adhesive layer and brittle glass. You will need a specialized tool that will allow you to evenly warm the case and carefully peel the lid without mechanical damage. Ignoring the requirements for tools significantly increases the risk of turning the repair into the purchase of new parts.
First of all, get a heat source, the best option is a professional thermo-air soldering station or a hair dryer, although some masters use heating platforms (separators). If you do not have such devices, you can use a household hair dryer, but you have to control the temperature by hand, which is less reliable. Also critical are suction cups for lifting glass, thin metal blades and plastic mediators that do not scratch the frame.
- 🔧 A set of precision screwdrivers (required the presence of a Torx bit) T5 or T6 screw-in).
- 🌡️ A dryer or heating platform for softening the glue (temperature near the 80-90°C).
- 📱 Screen/cover suction cup and set of plastic shoulder blades/mediators.
- 🧴 Isopropyl alcohol or special liquid B-7000 glue-residue.
⚠️ Warning: Never heat your smartphone with an open fire or on a kitchen stove – this is guaranteed to damage the battery and can cause it to bloat or catch fire.
Preparation of the workplace also plays an important role: the table should be clean, well-lit and have a non-slip coating. It is recommended to use a magnetic screw mat so as not to confuse them during assembly, since the Xiaomi Mi 8 uses screws of different lengths for different nodes. The absence of dust minimizes the risk of debris falling under the display or on the camera during operation.
☑️ Ready to disassemble
The process of heating and removing the back cover
The most critical step is to soften the adhesive compound that holds the back panel.The Xiaomi Mi 8 has a glass back cover that is glued around the perimeter, and in the center is often a logo, under which there may also be glue.Heat should be done evenly, driving a hairdryer around the perimeter of the device for 3-5 minutes, constantly monitoring the temperature with your hand (the body should become hot but tolerant to touch).
After sufficient warming up, you need to quickly but carefully insert a suction cup at the bottom of the back cover and pull up, creating a small gap. The resulting gap immediately injected a thin metal probe or blade, which is then replaced with a plastic mediator. Movements must be sliding, parallel to the plane of the smartphone to cut the adhesive layer, not break the glass.
The nuances of glue work
As you move around the perimeter, it is important not to enter the tool too deeply so as not to damage the plume (fingerprint scanner), which in some modifications or with a sloppy assembly can be laid close to the edge, although in the Mi 8 the scanner is on the screen. Pay special attention to the corners, as there the glue layer is often thicker, and requires more thorough warming up. If you hear a crunch, immediately stop moving and add heat.
| Heat zone | Warm-up time (dryer) | Temperature regime | Risks. |
|---|---|---|---|
| Perimeter of the lid | 3-4 minutes | 80-90°C | Glass cracks |
| Central part | 1-2 minutes | Up to 80°C | Battery damage |
| Corner zones | Dope. 30 sec. | 85-90°C | Fractures of frames |
| Lower end | 1 minute | 80°C | Microphone damage |
When the lid is completely separated, don’t try to remove it completely right away, make sure that no plumes are stretched. In the Xiaomi Mi 8, the back cover has no direct connections to the board, but it is better to be safe. The lid should be immediately cleaned of the old glue so that when it is reassembled it will lie flat.
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Use a thread (dental thread or string) to initially cut the glue around the perimeter after heating – this reduces the risk of damaging the glass with a blade.
Dismantling the protective plate and disconnecting the plumes
When you remove the back cover, you'll see the inside of your smartphone, where you'll see the battery packs most of the space, and the top of the board is a motherboard, which is covered with a black plastic safety plate, and this plate is mounted with a lot of screws of different sizes, and it's important not to confuse them, because too long a screw can penetrate the board through.
To access the connectors, you need to unscrew all the visible screws that fix the plastic lining. Use a magnetic mat or a piece of paper that has a pre-drawn screw layout on it to put them in the appropriate places. The screwdriver must be of high quality, with a magnetized sting, so that the screws do not fall into the case, where they are difficult to reach.
- 🔌 Turn off the plume of the main camera module by pulling it up with tweezers.
- 🔋 Carefully disconnect the battery connector from the motherboard (this is a must before any further work).
- 📡 Remove the antenna plume Wi-Fi/Bluetooth, if it interferes with access to the right sites.
After removing the protective plate and turning off the battery, further disassembly can be started, and a sudden movement can tear off the contact group, which will lead to the inoperability of the module.
⚠️ Warning: Always turn off the battery first! Even a brief circuit of the display connector or camera with the battery connected can burn the power controller on the motherboard.
If your goal was to replace the battery, then after removing the top plate and turning off the battery, you need to go to the bottom of the case, and there is also a plastic lining covering the bottom plume (sub-board), which connects the charging connector, microphone and speaker to the main board.
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The correct sequence of disconnection of plumes and screws is the key to successful assembly without unnecessary details.
Replacement of the battery and work with the lower fee
The battery in Xiaomi Mi 8 takes up a significant part of the internal volume and is glued to the frame with double-sided tape. Over time, this tape loses its properties or, conversely, it clings to death. You can not use metal tools to extract the battery, since a puncture of the lithium polymer battery will cause instant fire.
The recommended method of extraction is to use a thin fishing line or plastic card that is run under the battery from different sides, and you can pre-drip some isopropyl alcohol under the battery (if you have access to the edges) to dissolve the glue, and you need to act slowly, with sawing movements, gradually separating the cell from the housing.
The sub-board is mounted with multiple screws and plastic locks, and when you remove it, you have to be careful with the antenna contacts that provide the connection, they can fall out or get lost, which will lead to a deterioration in signal reception, and there is a vibrator on the lower board, which sometimes needs to be replaced.
When installing a new battery, make sure that its connector sits tightly on the board, and check the voltage with a multimeter if possible. Once you connect a new power source, take your time to twist the screws - first check if the device is switched on and charging is going on, which will save time in the event of a new part failing.
Assembly of the device and sealing of the housing
The Xiaomi Mi 8 is assembled in reverse disassembly order, but with one important addition - applying a new adhesive. Factory tightness is already broken, and without quality adhesive, the smartphone will collect dust and moisture, which will quickly lead to oxidation of the contacts. Use B-7000 glue or special adhesive tapes cut into the shape of the body.
Apply the glue with a thin strip along the perimeter of the frame, avoiding getting into the cameras and speaker. Let the glue dry a little (2-3 minutes) so that it becomes less fluid, then gently apply the back cover and press hard around the perimeter. For better fixation, you can use stationery rubber bands, stretching them across and along the body for 15-20 minutes.
- ✅ Make sure all plumes are connected before the final installation of the cover.
- ✅ Check all buttons and vibrations before screwing.
- ✅ Wipe the camera lenses from dust before closing.
After assembly, check the touchscreen, as sometimes when the cover is pressed heavily, the contact of the display plume may be broken. If the screen reacts with a delay or there are "dead zones", you will have to open the device again and reconnect the connector.
⚠️ Warning: Do not turn on your smartphone immediately after assembly if you have used liquid glue – let it fully polymerize within a few hours so that the alcohol vapors do not settle on the cameras.
Frequent errors and troubleshooting
In the process of repairing Xiaomi Mi 8 beginners often make typical mistakes that can cost the device life. One of the most common is damage to the plume of the display when the rear cover is not neatly removed, as it passes close to the heating and adhesive zone, and small screws are often lost or plastic latches break.
If the phone doesn't turn on after assembly, don't panic. First check if the battery is connected, and try to charge the device for 15-20 minutes. Sometimes the power controller goes into protection and takes time to activate. If the screen lights up but the image is not, check the density of the display connector.
Post-assembly communication problems often indicate that the lower board antenna contacts have not made it to their nests or have been lost during disassembly, in which case you will have to remove the bottom plastic lining again and check the position of the spring contacts.