How to carefully remove the back cover Xiaomi Redmi 4X: tools, risks and step-by-step analysis

Xiaomi Redmi 4X (codenamed santoni) is one of the most popular budget smartphones of 2017, but even after years of repairing it, owners face the need for a bloated battery, cracked camera glass or a replacement plume. The main problem when disassembling is the adhesive fixation of the rear cover, which often breaks when sloppy dismantling. In this article, we will discuss how to remove the lid without damage, what tools you will need and what to pay attention to not turn the repair into the purchase of a new case.

Let me warn you right away: Redmi 4X is not a "repairable" device like Fairphone or old Nokia. There are no screws under the lid, it's held back by double-sided tape and plastic latches around the perimeter. Disassembly errors can damage antenna contacts (network signal will deteriorate), cracks on plastic or even tearing off the plume of the fingerprint scanner. If you've never taken your smartphone off, you better contact the service. But if you decide to act on your own, follow the instructions below.

Preparation: tools and security

Before you start dismantling, make sure you have everything you need. The Redmi 4X requires care: one wrong move and the lid will crack along the antenna lines (not only is it aesthetically unpleasant, but it also makes signal reception worse).

• 🔧 Plastic blade (or mediator) to lick the lid. Metal tools will leave scratches!
• 🔥 Dryer or thermo-air station - for softening the glue (temperature 60-80)°C).
• 🧲 Suction cups (optional) – help lift the cover after heating.
• 📦 Container for screws - if you plan to disassemble further (in Redmi) 4X cruciform screws under the cover, size T3).
• 🧴 Isopropyl alcohol 90%+ — glue-residue.

⚠️ Warning: Do not use a household hair dryer at maximum power - it will overheat the plastic and melt the internal components. The optimal distance to the body is 5-7 cm, the temperature is not above 80°C. If you don’t have a thermal gun, heat the lid for 2-3 minutes, then let it cool for 30 seconds before Attempt to remove.

Also prepare the workplace:

• 🪑 Work at a table with good lighting (better to use a desk lamp).
• 🧹 Remove carpets or fabrics – a lost cog can roll and fall apart.
• 📱 Turn off your smartphone and remove it. SIM-card with memory card (when heated, plastic can deform and block the tray).

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If you don't have isopropyl alcohol, you can replace it with acetone or a varnish removal fluid, but they're more aggressive for plastic. Apply point-by-point and wipe immediately with a napkin.

Step 1: Heating the back cover

The glue that Xiaomi uses to fix the lid loses adhesion when it heats up, and your job is to heat the body perimeter evenly without overheating the individual areas. Start at the edges where the latches are.

1. Turn on the dryer at average power (if there is a temperature adjustment - set 60-70 ° C).
2. Direct the air flow to the lower part of the body (where the charging connector is) and warm up for 20-30 seconds.
3. Move the hair dryer to the left and right edges (areas of antenna lines), holding for 15-20 seconds on each.
4. Lastly, warm up the top (near the camera) - here the glue usually holds stronger.

⚠️ Warning: Don't heat the center of the lid - there's a fingerprint scanner board, overheating can make it go down! Also avoid direct hot air on the camera (its glass may crack).

After heating, try to gently apply the lid with a plastic blade in the area of the charging connector. If it does not respond, warm up for another 10-15 seconds. Do not apply force - the lid should move away with a slight click of the latch.

Heat the entire perimeter of the hull |

The blade is inserted into the gap at the charging connector |

No resistance at underdog (if any, warm up more)|

SIM-map and memory card retrieved-->

Step 2: Removing the lid – technique and risks

When the lid starts to move, follow the following algorithm:

1. Insert the blade into the gap by 1-2 mm and slowly lead along the edge, separating the latches. Start at the bottom, then move to the sides.
2. If the lid is stuck around the volume or power buttons, warm up the area again, and there are often undetached latches.
3. When all the edges are free, lift the lid at a 45° angle and remove it. Don't pull vertically upwards, you can tear the fingerprint scanner plume!

Here are the common mistakes and their consequences:

If the lid is not resistant to heat, maybe the glue is too old and dried.

• 🔄 Repeat heating, increasing the time to 40-50 seconds for each site.
• 💧 Apply a few drops of isopropyl alcohol into the gap between the lid and the case - it will dissolve the glue.
• 🔧 Use two blades at the same time, carefully widening the gap on both sides.

Step 3: Unconnection of the plumes (if required)

After removing the cover, you will see the insides of the Redmi 4X:

• 🔋 Battery (13 Wh, soldered to board).
• 📸 Camera module (13 MP, Sony) IMX258).
• 👆 Fingerprint scanner plume (thin flexible cable).
• 📡 Antenna contacts (metallic “tishes” on the edges).

If you've been removing the lid to replace the battery or repair the camera, you need to unplug the plumes. Redmi 4X has two:

1. The plume of the fingerprint scanner is attached to the motherboard with a small connector (it is under a metal cover that needs to be unscrewed).
2. The antenna plume is usually glued to the cover, but sometimes remains on the board.

⚠️ Attention: The fingerprint scanner plume is extremely fragile, don't pull it by the cable, just by the black plastic connector, and gently attach the connector with a plastic blade on the side, not on the top.

If you don't plan to take your smartphone apart further (e.g. just clean it from dust), you don't have to disconnect the plumes, you just need to gently put the lid next to you, avoiding the cables.

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The fingerprint scanner plume is the most vulnerable spot in the Redmi 4X, and it will cost 30 to 50 percent to replace, so be careful.

What to do after the lid is removed?

Now that the lid is removed, you have several options depending on the purpose of the disassembly:

If your goal is to replace the battery, consider: in the Redmi 4X it is soldered to the board, and you will need a soldering iron to dismantle. Without soldering experience, it is better to contact the service - the risk of damage to the board when the battery is separated is very high. Alternatively, use a special tool to remove soldered batteries (for example, a set with metal plates for warming up).

To clean the dust, you just need to blow the insides with compressed air (hold the balloon vertically so that the liquid does not splash!) and wipe the contacts with alcohol. Do not use cotton swabs - the villi can remain inside.

Build: How to install the lid back?

Putting the lid back in is as important as removing it.

1. Clean the surfaces of the old glue with isopropyl alcohol. The residue of the glue will reduce the adhesion of the new tape.
2. Stick a new double-sided tape around the perimeter of the case. You can use the original tape for Redmi 4X (Article XM-004X-ADH) or universal 3M.
3. Connect the plumes before you install the cover, make sure the fingerprint scanner connector sits down before you click.
4. Line the cover along the contours, then press it down, starting at the top (where the camera is) and moving down.

⚠️ Attention: If you don't replace the adhesive tape, the lid will hang around and the latches will break over time, and also check that the antenna contacts on the lid match the antennae on the board - if they don't touch, the network signal will deteriorate.

After assembly, turn on the smartphone and check:

• 📶 Network operation (call, check, check) 4G).
• 🔋 Charging (connect the cable – if the battery is not charging, check the contacts).
• 📸 Camera and fingerprint scanner.

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If the fingerprint scanner doesn't work after assembly, try reconnecting the plume, and often the problem is solved by re-installing the connector.

Alternative methods of removing the cover

If you don’t have a hair dryer or plastic shoulder blade, alternative methods can be tried, but they are riskier:

• 🧊 Cooling method: Put your smartphone in the freezer for 10 to 15 minutes. The glue will become brittle and the lid will move away easier. Risk: condensation can damage the board.
• 🧴 Glue solvent: Apply acetone or varnish removal fluid into the gap between the lid and the case.Risk: aggressive solvents can damage the plastic.
• 🔨 Screwdriver method: Carefully insert a thin screwdriver into the gap and turn. Risk: high chance of scratching the body or breaking the latches.

These methods are recommended to be used only as a last resort, for example, cooling is suitable if you are sure that there is no moisture inside the smartphone (otherwise, when turned on after disassembly, a short circuit may occur).

If you do decide to use a solvent, apply it point-by-point with a needleless syringe. Avoid hitting the motherboard and battery. After removing the lid, wipe the surfaces thoroughly with alcohol.

Frequent problems after disassembly and their solution

Even if you carefully removed the lid, after assembly, there may be problems, and here are the most common ways to fix them:

If Redmi 4X is not turned on after disassembly, check:

1. Is the battery connected (in this model it often departs when assembled sloppy).
2. Is the display plume damaged (if the screen is not shining, but the phone vibrates when charging).
3. Are the contacts closed on the board (look at the subject of foreign objects or drops of alcohol).

If the problem is not solved, the motherboard is probably damaged, in which case, you can not do without a diagnosis in the service center.

FAQ: Frequent questions about the dismantling of Xiaomi Redmi 4X