Nintendo Switch Trinket Guide

I completed an install of a modchip on about four different consoles, some of which I do not own. The installation went fine on all of them!

The modchip consists of a Trinket M0-based device, usually the RCMX86, to serve as an auto-injector for RCM-vulnerable devices.

Generally, a modchip will inject a small prebootloader payload from onboard storage into the console, which then chainloads a payload from the microSD card. The software I install to the modchip to preform this task is fusee-suite. Its functions are documented below. These modchips are fully unrelated to Team Xecuter modchips for Mariko units.

The original repository for fusee-suite can be found on GitHub.

I whipped up a generic usage guide for users and installers here.

Internal RCM-X86 usage guide

Congratulations on your new Nintendo Switch accessory!

This is a tool that seamlessly injects a payload to consoles vulnerable to fusee. You no longer need to inject payloads from an external device for the rest of your console's life.

Normal usage is for most users. In which:

• The console can be completely identical to stock consoles, and does not rely on a custom bootloader to start. Loading into custom firmware is optional and triggered manually by the user each time via manually entering RCM. This also means that updates do not pose any issue to the console's normal usage, but the user needs to rely on a jig to boot into custom firmware.

In conjunction with AutoRCM, advanced users have the option to coldboot into custom firmware every time. In this case, users should be wary of new updates, especially those (but not limited to) updates that modify the package1loader. These break tools like Hekate and atmosphere temporarily.

• The console cannot boot into a 100% stock environment with AutoRCM, but also can coldboot into custom firmware without a jig or any external accessories.

Alongside autoboot in Hekate's settings, this enables true, fully coldboot custom firmware.

Updating Horizon (Advanced Method)

If you do not use AutoRCM, then this mod does not interrupt the normal usage of your console in any way. You can ignore the following lines safely. If a new update is released that atmosphère doesn't support, you will still be able to boot into stock just like any other Nintendo Switch.

If you have enabled AutoRCM, you now require your console to have a microSD to boot at all. If your console does not have a microSD, you will not be able to chainload into Hekate to boot neither stock firmware, nor custom firmware.

You will no longer be able to boot into a truly stock configuration until AutoRCM is disabled. This is generally not an issue unless Nintendo releases an update that atmosphère cannot boot. In that circumstance, you should postpone the update until a new release of atmosphère is available to support it.

If you require the update immediately, or you accidentally updated -- disable AutoRCM and boot into stock, in the meantime. Custom firmware will no longer work on the updated NAND, but if you have an emuMMC on an older software version that atmosphère supports, it will continue to boot custom firmware without issue.

For clarification, using custom firmware while online is not and never has been a bannable offense. Piracy, cheating, and creating unsafe environments online (i.e. custom profile pictures) are. As long as you avoid these, then there is no issue with permanently booting into custom firmware and swapping between emuMMC and stock via the modchip. This is the configuration I have always used, and I have not used a stock firmware ever since 2019.

Updating RCMX86 software

This requires physical access to the modchip. This is more of a guide for the installer than the end-user.

Once a SAMD21 update payload is sent via a PC, press the reset button on the modchip twice, until a Windows Explorer window appears on your desktop. Then drag the software's UF2 file to the root of the modchip, at which point the modchip will reset and start running the new software automatically.

fusee-suite Settings

In the event the microSD is missing, or the payload cannot be found, Nintendo Switch boots into a prebootloader showing microSD mount status and the battery charge. Pressing VOL+ returns a list of options. VOL- navigates down in the list, VOL+ navigates up.

-----Browse-----

Browses for a payload to boot, off of the microSD.

-----Payloads-----

Detects and manages payload slots in every valid payload directory (payloadx.bin / bootloader/update.bin)

-----Backup/Restore-----

Options to back up and restore the console's raw physical NAND, specific partitions (SYS/USER/PRODINFO/BOOT0/BOOT1), or just BOOT0/BOOT1.

-----Bootlogo-----

Manipulate, set, or fully remove pre-boot splash screens.

-----Update-----

Enters SAMD21 update mode.

-----Mount-----

Mounts a memloader universal mass storage (UMS) tool over USB.

-----Battery Calibration-----

Accounts for and corrects uncalibrated batteries. Please also check the calibration FAQ.

This occasionally requires the users to physically disconnect and reconnect the battery for the console to turn on once this action has been taken.

-----Power-----

Powers the console off.

Troubleshooting

• I accidentally updated and my Switch receives an error when trying to boot! Disable autoRCM as mentioned in this paragraph.
• Nintendo Switch does not boot and has a black screen

The modchip is likely not attached correctly, while AutoRCM is enabled. Check one of the following straps: 3.3V, GND, or DATA+/DATA-.

• Nintendo Switch boots stock, but not into RCM payloads

One of the DATA+/- are not connected.

Alternatively, the modchip could be short-circuiting with the metal RF shield on the back of Nintendo Switch. Please make sure to properly shield the top of the modchip and the wires connected to it.

Alternatively, the 3.3V line is not connected.

• Nintendo Switch does not enter RCM!

Has the hardware been modified recently? Please check the Joy-Con's rails, both the inside and the outside. The outer parts may have dust or debris covering the metal contacts. If not, the user's jig may also be dirty. If both of these are correct, then it's likely that the ribbon cable of the Joy-Con slot may be slightly torn, making RCM entry impossible without removing the NAND.