Disassembly Xiaomi Mi 4: a complete guide with photo and expert advice

Xiaomi Mi 4 is the legendary smartphone of 2014, which is still used by many users. However, as you age, even the most reliable equipment requires repairs, from replacing the battery to cleaning the connectors or recovering from a fall. If you decide to disassemble the device yourself, this article will help you to do it right, avoiding the typical mistakes.

It is important to understand that disassembly is not a warranty event – after opening the case, Xiaomi’s official service will refuse free maintenance. But for Mi 4 owners who have long since expired their warranty, self-repair often becomes the only economically viable solution. We will discuss each step in detail: from preparing tools to assembling back, with an emphasis on the unique features of the design of this model (for example, non-standard fastening of the battery plume).

Preparation for disassembly: tools and security measures

Before you start, make sure you have everything you need. To disassemble the Xiaomi Mi 4 you will need:

• 🔧 Plastic blade (or mediator) - to separate the back cover without scratches.
• ⚙️ Cross-sized screwdriver PH00 — hull-rotor.
• 🔋 Suction - will help to suction the screen if you need to remove it.
• 🧲 Magnetic mat or container – to avoid losing small screws.
• 📸 Smartphone for photography – fix the location of the plumes before disconnecting.

Pay special attention to the workplace: it should be clean, well-lit and without static electricity (ideally an antistatic mat). Mi 4 contains fragile elements such as a glass rear panel (in some versions) and thin plumes. One careless jerk - and you can damage the display module or camera.

⚠️ Warning: If your Mi 4 has been in water or has been hit hard, disassembly can be dangerous! corrosion on the board or a cracked battery can cause a short circuit.

Step 1: Removing the back cover

Start by turning off your phone and retrieving it. SIM-The back cover of the Mi 4 is attached to the latches, but there is a nuance: unlike later Xiaomi models, there are no special notches for the shoulder blade:

1. Place the plastic blade in the gap between the lid and the body at the charging connector.
2. Smoothly drive the blade along the edge, alternately snapping the clamps. Don't force - the lid should move with light resistance.
3. After separation of one side, tuck the lid with your fingers and remove it completely.

Under the lid, you'll see the battery, the motherboard and the plumes. Don't pull the plumes, they're fragile! If the lid doesn't lend itself, check if the latches at the volume buttons or the camera are undetected.

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If the latches are too tight, slightly heat the edge of the body with a hairdryer (temperature not higher than 50 ° C).

Step 2: Shutting off the battery

Before you continue, be sure to disconnect the battery. In the Mi 4, it is connected via a JST 1.0 connector with a white plastic latch.

1. Carefully tuck the latch with a plastic shoulder blade or nail.
2. Pull the plume up - it should come out effortlessly.
3. Fix the plume with tape to the body so that it does not interfere with further disassembly.

If the latch broke (which often happens in older devices), you can put a tail on the side with a thin screwdriver, but act extremely carefully - damage to the battery contacts can lead to fire during subsequent connection.

⚠️ Warning: Never use metal tools to disconnect the battery! even micro-circuit can disable the power controller on the motherboard.

Step 3: Removing the motherboard

The Mi 4 motherboard is mounted on 12 screws of varying lengths, and here lies the main trap for beginners: if you confuse the screws during assembly, you can damage the board!

• 📏 Place the screws on the magnetic mat in order of their extraction (for example, from left to right).
• 🔍 Take a picture of each screw’s location – the Mi 4 uses 2.5mm, 3mm and 4mm screws.
• 🛠️ Use a magnetic tip screwdriver so that the screws do not fall out.

After removing the screws, carefully tuck the board with a plastic blade, starting from the upper edge (from the headphone jack side).

- Display plume (wide, black).

- Camera plume (thin, gray).

The home button plume (if present in your modification).

All of them are attached to latches that must be opened beforehand.

Step 4: Dismantling the screen (optional)

If you need to replace the display module or touchscreen, you have to take the screen off. In the Mi 4, it's glued around the perimeter, and there are two options:

1. Heating method: Use a hair dryer (60-70°C) to soften the glue. Driving a plastic blade along the edge, gradually separating the screen. Risk: overheating can damage the matrix.
2. String method: String a thin guitar string or line under the screen and cut the glue. It's safer, but longer.

Important: in the Mi 4, the display plume runs under a metal frame. Don't pull the screen too hard, you can tear the plume! If the screen cracks, tape it so that the shrapnel doesn't hurt your hands.

Step 5: Replace the battery

The battery in the Mi 4 is one of the most vulnerable parts, and over time it swells up, loses capacity, or refuses to hold charge.

1. Unplug the old battery with a plastic spatula. If it swells, be very careful, because the risk of puncture is high!
2. Clean the area under the battery from glue residues with alcohol or acetone.
3. Stick the new battery onto a double-sided tape (included). Connect the plume and check the voltage with a multimeter (should be ~3.7-4.2V).

Tip: When buying a battery, choose a PCB, cheap, unprotected models can swell or ignite.

The original Xiaomi BM43 (if you can find it).

Analogues from Patona or Baseus with overheating protection.

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Never use metal tools to work with the battery! even a microscopic scratch on the contacts can lead to short circuit.

Step 6: Assembly of the device

Assembly is no less important than dismantling.

• 🔄 Make sure all the plumes are connected to the end (the snap of the latch should be heard).
• 🔧 Write the screws in reverse order, starting with the longest.
• 📱 Before final assembly, turn on the phone with the battery connected, but without the lid - check the health of the screen, camera and buttons.
• 🧹 Remove dust from speakers and microphones with compressed air.

Typical errors in assembly:

- Rear cover skewed (latches not evenly fixed).

- Forgotten screw (leads to backboard).

- Damaged touchscreen plume (screen works but does not respond to touch).

If the phone does not turn on after assembly, check:

1. Is the battery connected?

2. Won't the display plume be hushed up?

3. whether all screws are in place (the absence of even one can cause a circuit).

Frequent problems and their solutions

Even with a careful disassembly, there can be problems.

If after disassembly there are artifacts on the screen (strips, flickering), the flexible plume or matrix is probably damaged. In this case, you will need to replace the display module. For the Mi 4, screens labeled JDI NT35590 or AUO B116XW03 are suitable - check compatibility with the seller.

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If the phone warms up or discharges quickly after assembly, check if the case is locked somewhere on the board. Sometimes the screws can touch the contacts, causing increased power consumption.

FAQ: Answers to Frequent Questions