Disassembly Xiaomi Mi 4S: a complete guide with photos, schemes and expert tips

The Xiaomi Mi 4S is one of those smartphones that, despite its venerable age (the model came out in 2016), is still in demand due to its balanced performance and maintainability. However, disassembling this device has a number of hidden difficulties that are not written about in standard instructions, such as the fragile plume of the fingerprint scanner or the unobvious battery mount, which can be damaged if you sloppy dismantle.

In this article, you’ll find step-by-step analysis of the photos, a list of tools you need, and unique tips for working with specific Mi 4S nodes – from removing the back cover to removing the motherboard. We’ll also tell you what mistakes beginners most often make (and how to avoid them), and give you tips for diagnosing faults before disassembly. If you plan to replace the battery, display or clean the connectors, this guide will help you get everything right the first time.

Preparation for disassembly: tools and security measures

Before you start disassembling the Xiaomi Mi 4S, make sure you have everything you need. The absence of even one tool can damage the body or internal components.

• 🔧 Plastic mediators (2-3 Pc.) - for careful slinging of the lid and plumes.
• 🔨 The screwdriver. PH00 — for the rear cover screws (normal) PH0 won't fit!).
• 🔋 Suction cup for display - will help to remove the screen without scratches.
• 🧲 Magnetic mat or tray - so as not to lose small screws (them in Mi) 4S 12 pieces).
• 🔥 Dryer or thermo-air station - to soften the glue under the battery.
• 🧴 Isopropyl alcohol (90%+) — Cleaning contacts and removing glue residues.

Also, prepare the workspace: it should be well lit, without dust and static electricity, ideal for a table with an antistatic mat, if not, at least ground by touching a metal object (for example, a heating battery).

⚠️ Attention, Mi battery 4S It's double-mounted, and in addition to the glue, it's fixed by a metal frame with latches, and if you try to tear it off without heating it up, you can tear the plume or damage the board!

Step 1: Remove the back cover and battery

Start by turning off your smartphone and retrieving SIM-maps:

1. Heat the back cover with a hair dryer (temperature no higher than 60°C) around the perimeter for 1-2 minutes. This will soften the glue.
2. Insert a plastic mediator into the gap between the lid and the body (start at the lower left corner where the antenna is located). Carefully drive the mediator along the edge until the lid begins to move away.
3. Remove the lid and put it aside, and underneath it you'll see 12 screws (of varying lengths!) and a fingerprint scanner plume.

Now you need to disconnect the battery.

• 🔌 Disconnect the battery plume from the motherboard (use a plastic mediator to tamper with the connector).
• 🔥 Heat the battery with a hair dryer (temperature) 70-80°C) during 3-4 It'll melt the glue.
• 🧊 Subdate the battery with a plastic blade, starting from the upper right corner (there is less risk of damaging the plumes).

⚠️ If the battery is swelling, don't heat it up, it could cause fire, B-7000) and carefully separate the battery by a millimeter.

Step 2: Dismantling the motherboard and plumes

Once the battery is removed, you can start removing the motherboard, and the key here is not to confuse the order of the plumes to shut down so that the connectors are not damaged.

1. Unscrew all the screws fixing the metal plate above the board (they are of different lengths - remember the location of each!).
2. Disconnect the plumes in this order: The fingerprint scanner plume (fragile, easily torn!) Display plume Touchbar main camera plume
3. Carefully tuck the motherboard into a plastic spatula and remove it. Be careful, there are antenna wires underneath the board that are easy to tear off!

If you're disassembling the Mi 4S to replace the charging socket, notice that it's soldered to the board, that it requires a soldering station and microelectronics experience, and that's something that the beginner should trust to the professionals.

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Before disabling the plumes, take a picture of their location on the board - this will help to connect them correctly during assembly.

Step 3: Removing the display and touchpad

The Mi 4S display is glued around the perimeter, so it will require a thermo-air station or a hair dryer to remove it.

1. Heat the screen around the perimeter (60-70°C) for 2-3 minutes. Start at the bottom of the plume.
2. Stick the suction cup to the bottom of the display and gently pull it up. If the screen doesn't respond, repeat the heat.
3. As soon as the gap appears, insert plastic mediators (for 2-3 on each side) and slowly lead them along the edge.
4. After removing the display, disconnect the plume of the touch panel (it is under metal protection).

Important: in the Mi 4S, the display and the touchpad are glued together, and if you're replacing only the glass, you're going to need to split the layers with a thread or a tool, and it's a laborious process that you're going to trust to the wizard.

Common Mistakes in Disassembly and How to Avoid Them

Even experienced craftsmen sometimes make mistakes when working with the Xiaomi Mi 4S. Here are the most common of them:

• 🔧 Mixed screws - in the Mi 4S If you screw a long screw into a place for a short one, you can damage the board.
• 🔥 Battery overheating - temperature above 80°C can cause it to swell or even ignite.
• 📱 Damage to the plume of the fingerprint scanner - it is thin and fragile, easily breaks with careless extraction.
• 🔌 Break antenna wires - they pass under the motherboard and can come off when a sharp movement.

To avoid these problems:

• Place the screws in groups (for example, on a magnetic mat with marks).
• Use a thermocouple to control the heating temperature.
• Turn off the plumes only with plastic tools.
• Before assembly, check all connectors for dust or oxidation (clean with isopropyl alcohol if necessary).

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The most common failure in disassembling the Mi 4S is a broken plume of the fingerprint scanner, which, if damaged, will stop working, and the replacement of the plume will cost 30-50% of the cost of the smartphone.

Diagnostics of malfunctions before disassembly

Before you take apart the Xiaomi Mi 4S, make sure that the problem does require physical intervention.

• 🔋 Battery discharges fast → Check battery consumption in Settings → Battery. If it's the application's fault, reinstall it.
• 📵 The network is not working. → Try resetting your network settings (Settings) → SIM-maps and mobile networks → Resetting settings).
• 🔊 No sound in the speaker. → Check if the headphone jack is contaminated (sometimes the system “thinks” the headphones are connected).
• 📱 The sensor is not working. → Connect your smartphone to your PC and check if the screen responds to commands through ADB.

If the problem persists, here are the symptoms that definitely need to be disassembled:

If you are not sure about the cause of the malfunction, use test codes to diagnose:

#4636## - information about the battery and network
#6484## - Sensor and display test
##0*## - LCD (Colors)

Build Xiaomi Mi 4S: nuances and verification

The smartphone should be assembled in reverse order, but there are several key points:

1. Before installing the battery, clean the contacts on the board and battery with isopropyl alcohol.
2. Stick the battery to double-sided tape (e.g. 3M 9448A) or special glue. Don't use superglue!
3. Make sure all the plumes are tightly inserted into the connectors. If the plume is dangling, check if the connector is bent.
4. Twisting the screws cross-cross to avoid skewing the board.
5. After assembly, check the operation of all components: 📶 Sensor and display 🔋 Charging (connect the cable and check the indication) 📷 Camera and fingerprint scanner 🔊 Speakers and microphone

If something doesn't work after assembly, don't panic. Go back and check:

• Are all the plumes connected?
• Is there a cable out there?
• Are all the screws twisted (but not pulled!)?

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After assembly, turn on your smartphone and check the temperature of the case. If it warms more than usual, most likely somewhere short circuit (check the charge for damage).

FAQ: Frequent questions about the dismantling of Xiaomi Mi 4S