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A trimmed Wii motherboard is the heart of any Wii portable or Wii project. This manual will guide you through the process of disassembling the Wii, installing the necessary software, and then trimming the board.

The trim this guide entails is for 4 layer motherboards, revisions RVL-CPU-40 and newer. See the Wii Revision Identification Guide to identify your Wii's revision.

If trimming a 6 layer board, see The Definitive Wii Trimming Guide 6-layer Expansion.



Before continuing with this guide, ensure you have the the required tools and parts specified above.

  • A rotary tool with a diamond cutting disc such as a Dremel
  • A phillips head screw driver
  • A triwing screw driver
  • A USB drive compatible with Wii homebrew
  • A SD card 4GB in size or smaller

Validation of your trim will also require power sources for the voltages required by the Wii, and a display.


Be aware that a rotary tool can be dangerous when proper safety considerations are not made. The Wii motherboard you will be cutting is made of fiberglass, copper, and other components. To protect you from material that may fly while trimming the board, ensure you have proper personal protective equipment (PPE) work. This should at minimum include safety glasses and gloves.

If you've never used a rotary tool before, work with someone who has and practice handling the tool while making cuts.

Prepare the Wii's Software Before Trimming

Trimmed Wii's require software mods to be performed before cutting in order for them to function. The first step is getting access to The Homebrew Channel. This can be achieved in several ways, the most popular being via the letterbomb exploit.
On the generator linked, enter your Wii's MAC address, found in the Wii's system settings. Copy the generated files to a SD card formatted as FAT32. Once done:
  • Insert the SD card into the Wii
  • Ensure the system calendar is set to the correct date
  • Navigate to the system messages and you should see a red envelope
  • Open the letter and follow the on-screen prompts and install The Homebrew Channel
Now that custom software can be ran with The Homebrew Channel, install RVLoader. Read the thread & follow the instructions. Installation can be summarized as downloading the zip archive provided, unzipping it's contents on an SD card formatted as FAT32, and running the installer from The Homebrew Channel. Make sure to consider the following tips:
  • If your Wii still has an SD card inserted, you may need to press "1" on the WiiMote to change to the USB drive
  • Enable VGA if you intend to wire your screen to it later. You can alternatively enable it later
  • Enable "patch out Wi-Fi" by setting it to "yes" - failing to do so will result in a board that will not boot
If your Wii boots to RVLoader when powered on, you're ready to trim the motherboard.

Prepare the Wii's Software Before Trimming

Open the Wii's Case

Follow the tear down images to open the Wii in order to gain access to its internals.
  • Unscrew the battery tray as shown and slide it out from the Wii
    • If you plan on relocating the MX chip you may reuse the battery, check it with a multimeter to make sure it's still good
  • Remove the previously hidden screw, as shown
  • On the bottom of your Wii console when laying down, there are two small adhesive paper coverings hiding two triwing screws
    • Remove the paper with a craft knife
    • Unscrew both screws
  • The last screw holding on the front face plate is hidden under a rubber foot. Remove it with a craft knife
    • Remove the screw hidden underneath as shown
  • A small cable for the disc drive light will be holding the faceplate to the Wii - remove it and the faceplate
  • Remove the GC Memory Card and Controller doors from the top of the Wii
    • The doors pull out with a little force
    • If you have a Wii without GameCube controller ports, there will be small squares on the top of your Wii that can be removed with a craft knife
  • Remove the three screws shown from the controller plate
  • Once the screws are removed, the plastic controller plate will pull up from the console
  • Underneath, there are 4 more screws to remove - 2 triwing and 2 phillips, remove all 4
  • On the bottom of the Wii there are adhesive papers covering the screws just as there were on the faceplate
    • Remove the adhesive paper covering the screws as shown
    • Remove the 3 triwing screws
  • Remove the 2 feet shown from the Wii with a craft knife or small flat head screw driver
  • Remove the two triwing screws from inside the screw holes as shown
  • The larger top casing can now lift off from the Wii
  • You should now have access to the inside of the Wii

Removing the Motherboard From the Wii

Continue to free the motherboard from the Wii, following the tear-down images.
  • The shielding present upon opening the Wii just lifts off. There is nothing holding it down
  • Remove the 4 screws shown that are holding the optical drive in place
  • The disc drive will be attached by two different cables
  • Lift up on the FFC connector to remove the flat cable
  • Pull the connector out to remove the white set of cables
  • Set the optical drive aside
  • Remove the following screws from the black plastic bracket at the front of the Wii and remove the bracket
  • After, remove the following screws and shielding as shown
  • Remove the screws as shown from the fan
  • Remove the fan's connector from the Wii
  • Remove the 2 screws shown and lift away the first plastic bracket
  • Next, remove 3 screws in order to remove the remaining bracket
    • One screw is hidden underneath of one of the WiFi antennas, to remove it bend the plastic tabs holding the PCB in place back and remove the board
  • Lift the bracket away once the screws are removed
  • Remove all of the screws shown holding the metal shielding to the motherboard
  • Remove the shielding and remove the 4 screws from the heat sink
  • Remove the WiFi module and Bluetooth modules

Prepare the Board for Trimming

Before cutting the board, draw an outline of the planned trim with a permanent marker. Every project may require a slightly different trim, the one pictured in this guide is for a G-Boy kit.

Once your outline is made, remove any large components along the the drawn path.
  • Using a pair of pliers grab the components as shown, twisting them will remove them from the motherboard
  • Make sure to remove any plastic left behind

Cutting the Motherboard

Cut out the portion of the motherboard outlined previously. This video provides an overview of the process but keep the following points in mind:
  • Always wear your safety glasses and preferably gloves when cutting a motherboard
  • Ensure you have a solid grip on both the rotary tool as well as the motherboard
  • When sanding the edges of the boards, sand at bit of an angle, this will help in removing shorts
  • Sand starting at 180, then go to 200, then 300, 400, 600, 800, and 1000 grit sand paper. Any higher is optional.
Sanding the edges is not optional. Sand with the specified grits and until there are no visible shorts between each copper layer of the PCB. The copper on the edge of the board should be smooth to the touch and be shiny around the full edge of the board.

Check for Shorts

Before continuing, verify the trim has no shorts between the layers. Use a multimeter to check the resistances between the various voltage rails. Easy points for each voltage rail are provided in the image. You can use the spreadsheet from Nold's Wii Trim Resistances Thread to aid you in tracking your measurements.
If you find any of your measurements are significantly lower than those detailed in the thread, re-sand the edges of the motherboard and check for other potential causes of a short circuit between the layers.

Check for Shorts

Remove U10 & U5

U10 generates a signal necessary for the Wii to boot. This means it must be relocated so the trimmed motherboard functions properly. U10 is traditionally relocated to the location of U5, meaning it must also be removed.

The best method to remove U10 and U5 are shown in this video. U10 is located next to the MX chip (as shown in the video) and U5 next to the CPU and GPU.

Relocate U10

Before we solder the U10 to the board, we must first clean the pads where U5 was previously.

  • Remove the resistors and capacitors around where the U5 was
  • Use flux and solder wick to clean up the solder left behind after removing the U5
  • Scrub this area with a toothbrush and some IPA to clean any flux residue
  • Place the U10 down and solder each of the legs
    • Be sure to bridge the front 3 legs together

Wire U10 to its Via

The U10 must now be connected to a via connected to the GPU. This completes the U10 relocation.

  • Solder a piece of magnet wire to the leg of the U10 as shown
  • Run the wire through the via shown in the image
  • Solder the other end of the wire into the via on the back of the motherboard as shown
See photos for full details.

Remove the LDO (Optional)

The LDO is a linear regulator on the Wii Motherboard that supplies the 1.8V rail required by the system. Some regulator solutions opt to not provide a 1.8V rail and instead rely on the LDO to supply it.
If your build will use custom regulators that provide 1.8V, you should remove the inefficient LDO from the board.

The LDO can be removed with a hot air station, or with an amply powerful soldering iron. Removing the LDO with a weaker iron can still be achieved by removing thermal mass, demonstrated in this video provided by Wesk on the forums.

06/20/2024 07:07:39