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iPhone 12 Pro Max back glass replacement

DifficultyDifficult
Steps34
Time required2 to 3 hours
DisplayOLED
PortLightning

Introduction

Use this guide to replace a cracked or shattered back glass on the iPhone 12 Pro Max. The glass is bonded to the frame, so you need a way to separate it safely and a clean surface to bond the new one. Written for repair shops, with an illustration and the safety notes for every step.

Before you start. This guide is for trained technicians. Lithium batteries can overheat if damaged, so discharge below 25%, never use metal tools on the cell and work on a non-flammable surface. Always check the procedure for your exact part before opening the phone.

What you need

Parts

Trade prices, ex VAT.

Replacement back glass
Buy this part
Back glass adhesive
Buy this part
Repair tool kit
Buy this part

Tools

Pentalobe P2 (0.8mm) screwdriver
Phillips #000 screwdriver
Suction cup
Plastic picks
Spudger
Tweezers
Heat plate or heat gun
Isopropyl alcohol (90%+)
Screw tray or magnetic mat
Clear packing tape
Plastic scraper

Step 1Power down and discharge

  • Power the iPhone 12 Pro Max off. If it still turns on, let the charge drop below 25% before you open it.
  • Work on a clean, non-flammable surface with good light.
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WarningA cracked back glass can also mean the frame or battery took a knock. Check the battery for swelling before you go further.

Step 2Set up a screw tray

  • Every screw in this phone has a place, so lay out a tray or mat and put each screw down in the order it came out.
AABBCCDDPlace each screw where it came from

Step 3Tape over cracked glass

  • Cover the back with overlapping strips of clear packing tape to hold the shards together.
  • Wear eye protection if the glass is shattered.
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Step 4Check what is under the damage

  • Look at the camera ring, the frame edges and the wireless charging area for cracks or bends.
  • If the frame is bent or the camera lenses are broken, quote for those repairs as well.
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Step 5Remove the bottom screws

  • Use a pentalobe P2 (0.8mm) screwdriver to remove the two screws either side of the Lightning port.
  • Put both in the first spot on your screw tray.

Step 6Warm the bottom edge

  • Warm the bottom edge of the screen with a heat pad, or a heat gun on a low setting, for about a minute.
  • Warm, not hot: roughly 60 to 80 °C. Too much heat can damage the display and the battery underneath.

Step 7Attach the suction cup

  • Press a suction cup onto the screen just above the bottom edge, clear of any cracks and the curved edge.
  • If the cup will not stick, add a piece of tape and try again.

Step 8Open a small gap

  • Hold the phone firmly and pull the suction cup up with steady force.
  • You only need a gap big enough to slide a pick into.
CautionThe display is held by waterproof adhesive and clips. Do not try to lift the whole screen in one go.

Step 9Insert a pick

  • Slide a plastic pick into the gap at the bottom-left corner.
  • Remove the suction cup.

Step 10Cut the adhesive: bottom and left

  • Slide the pick along the bottom edge, then back round up the left side.
  • Re-warm the edge if the adhesive resists.

Step 11Work along the hinge side carefully

  • The display cables run along this side, so keep the pick no deeper than about 3mm.
  • Move up the side in short strokes. Stop and warm it again if it sticks.
CautionA deep pick on this side can cut the display or sensor flex cables.

Step 12Release the top edge

  • The front camera and sensors sit near the top, so keep the pick shallow here too.
  • Run it along the top edge to release the last of the adhesive.

Step 13Lift the display gently

  • Open the display from the bottom edge, like a book, to about 90 degrees.
  • Do not pull it flat: the flex cables are still connected.

Step 14Support the display

  • Prop the display against a small box or stand so it cannot fall back.
  • Keep the cables free of tension.

Step 15Find the connector bracket

  • Look for the metal bracket covering the battery connector and the display cable connectors on the logic board.
BATTERYIllustration, not to scale

Step 16Remove the bracket screws

  • Remove the screws that hold the bracket down.
  • Note which tray position each one goes in. They differ in length.
BATTERYIllustration, not to scale
CautionCheck each screw's length against your tray before it goes back in. A screw that is too long can damage the board.

Step 17Lift the bracket away

  • Lift the bracket with tweezers or the end of a spudger and put it aside.
BATTERYIllustration, not to scale

Step 18Disconnect the battery first

  • Gently lift the battery connector straight up with the flat end of a spudger.
  • Bend it slightly away from its socket so it cannot touch and reconnect by accident.
BATTERYIllustration, not to scale
WarningAlways disconnect the battery before any other connector.

Step 19Disconnect the display cables

  • Lift the display connector and the touch connector with the flat of a spudger.
  • Lift the front sensor assembly connector the same way, keeping each cable straight.
BATTERYIllustration, not to scale

Step 20Remove the display

  • Lift the display clear of the phone.
  • Put it down on a soft, clean surface.

Step 21Remove the parts inside the frame

  • Take out the battery, Taptic Engine, loudspeaker, charging port assembly, cameras and logic board so the frame is empty.
  • Note every screw position as you go, and keep each part with its own screws.
BATTERYIllustration, not to scale
CautionThis is the longest part of the job. Our other guides show how to remove each part safely.

Step 22Mount the frame

  • Fix the empty frame in the holder of your laser machine or heat plate, with the back glass facing up.
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Step 23Separate the old glass

  • A laser machine is the safest way to separate the glass from the frame. Follow the machine's instructions for the iPhone 12 Pro Max.
  • If you have no laser, warm the frame to soften the adhesive and work a thin tool under the glass. This is riskier for the frame.
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WarningDo not pry hard. A bent frame cannot be fixed, and glass shards are sharp.

Step 24Clean the frame

  • Remove all old adhesive and glass from the frame with isopropyl alcohol and a plastic scraper.
  • Let it dry completely.
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Step 25Move across parts that stay

  • Move the camera lens frames, any retaining brackets and the wireless charging parts to the new glass if they are not already fitted.
  • Check each one is seated flat and clean.
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Step 26Fit the new back glass

  • Apply the new adhesive to the frame, then lay the new glass on it, lining up the camera cut-out first.
  • Press it down evenly and hold it in a clamp or press for the time the adhesive maker recommends.
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Step 27Refit the parts inside the frame

  • Refit the logic board, cameras, charging port, speaker, Taptic Engine and battery in reverse order, putting every screw back where it came from.
BATTERYIllustration, not to scale

Step 28Reconnect the display cables

  • Lay the display next to the phone and press each connector down until it clicks: display, touch, then the front sensor assembly.
BATTERYIllustration, not to scale

Step 29Reconnect the battery

  • Press the battery connector into its socket and refit the bracket and its screws in their original positions.
BATTERYIllustration, not to scale

Step 30Test before sealing

  • Turn the phone on and check the screen, cameras, flash, speakers, charging and wireless charging before you seal it.
Touch and displayFace ID, cameraEarpiece, sensorsCharging, battery

Step 31Power off and fit a new seal

  • Remove any old adhesive from the frame and clean it with isopropyl alcohol.
  • Fit a new pre-cut display seal so water resistance is restored as far as possible.
NoteA fresh seal restores much of the protection but not all of it, so do not promise customers the original water-resistance rating.

Step 32Close the display

  • Hook the top edge in first, then lower the display and press down along the bottom.
  • Press firmly all round the edge for about 30 seconds.

Step 33Refit the bottom screws

  • Refit the two pentalobe screws either side of the Lightning port.
  • Tighten until snug. Do not over-tighten.

Step 34Final checks

  • Check the glass sits flat all round with an even gap, then wipe it clean.
  • Tell the customer the water resistance may not be as good as new.
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Conclusion

Check the new glass sits flat with an even gap all round, then test the cameras and wireless charging. Recycle the old glass carefully, as the edges are sharp.

Common questions

Do I need a laser machine?

A laser machine is the safest way to separate the glass from the frame on most models. You can use heat and a thin tool instead, but there is a higher risk of bending the frame.

Will wireless charging still work?

Yes, as long as the wireless charging parts are moved across or included and seated flat. Test it before you finish.

Do I need a new camera ring or lenses?

Often the lens glass is already in the new back glass. Check what your part includes and compare it with the original.

Will this affect water resistance?

Replacing the back glass breaks the factory seal on the iPhone 12 Pro Max. New adhesive restores a lot of protection but not all of it, so don't promise the original rating.

More iPhone 12 Pro Max guides

Screen replacement Battery replacement Charging port replacement All iPhone 12 Pro Max guides