Disassembly/Repair of the mobile device Xiaomi Mi 4i (Xiaomi Mi 4i 2015015) with each step description and the required set of tools.

Use the ejection tool (aka Needle) or Paperclip. Push the tip all the way into the hole until the tray ejects, and then pull the tray of SIM cards out.

⚠️ Pay attention! The tool must be inserted into a hole on the edge of the phone's housing. Do not press too hard. It may break the tray eject mechanism.

Using a spudger or a plastic pick, carefully, around the edge, detach the back cover clips, and remove it.

Do not insert the tool deeply or bend it. Otherwise, the housing may be tampered with or damaged.

⚠️ Be careful when opening the cover from the volume and power buttons side. Thin cable and fragile buttons are straightforward to damage.

Using a screwdriver (Phillips 1.5 mm PH000), unscrew 13 screws.

Remove the cover with antennas. The cover protects the printed circuit board (PCB). Try to lift the cover by the edges and not push anything between them to not accidentally touch or short-circuit anything on the PCB.

Disconnect the battery connector as soon as possible.

ℹ️️ The Xiaomi Mi 4i model has a battery BM33 with 3120 mAh capacity (aka rechargeable battery).

⚠️ It is highly recommended to disconnect the connector to avoid possible short circuits during disassembly.

Also, try not to use a metal tool to disconnect the rechargeable battery connector or do it carefully.

Using a screwdriver (Phillips 1.5 mm PH000), unscrew three screws.

Remove the loudspeaker assembly with antennas.

Remove the battery. Be careful. The battery may be glued tight, also under the battery two flat cables.

Carefully disconnect the connectors and remove the coaxial cable, preferably from the edge.

Disconnect the LED cable for navigation buttons connector, inter-board sub-screen cable connector on the daughterboard.

⚠️️ Do not pull on the cable or pry it with a sharp tool, the connectors are pretty weak and break easily, or the cable falls out of the end (lug).

Using a screwdriver (Phillips 1.5 mm PH000), unscrew two screws holding the charging port.

Remove the sub-board. It is glued to the frame with metalized tape, so to facilitate the process, the sub-board can be heated a bit.

ℹ️️️ The sub-board contains a charging port (Micro USB), micro-phone, spring contacts for the speaker, and an antenna unit.

⚠️️ It is not necessary to insert the tool underneath when removing the sub-board. Internal components could be damaged.

Disconnect the connectors on the motherboard, and remove the front (selfie) camera, earpiece speaker.

Using a screwdriver (Phillips 1.5 mm PH000), unscrew two screws on the motherboard.

Pry up the connectors of power volume buttons cable, display cable, touchscreen cable, inter-board cable.

⚠️️ Be careful when removing the cables from the connectors, the cables are pretty thin, and it is easy enough to break them or damage the contact tracks inside.

Carefully remove the printed circuit board. There is no need to use a lever or try to reach the board by force. Make sure that nothing is getting in the way or holding the board.

⚠️️ Do not bend the circuit board when removing it or push tools under it. Unbeknownst to yourself, you can damage components or cables from the inside.

Pry up the connector and remove the main camera.

ℹ️️️ In the display frame remained: