MODXO ApexusNULL

An editable KiCad reconstruction of the Modxo Lite V1 for the original Xbox. The layout was reconstructed from board photographs, microscope images, continuity measurements and existing Modxo research, with the reference board used as the physical baseline.

Hardware

• RP2040 QFN-56 processor, 12 MHz crystal and W25Q128JVSIQ 128 Mbit (16 MiB) flash.

• USB-C and BOOT controls for programming.

• Two onboard indicators: WS2812B-MINI-V6 addressable RGB LED and a separate blue LED.

• RGB, expansion I2C, HDD/LAN, D0, UART, LCD and Xbox I2C connections.

• 36.6 × 36.6 mm overall envelope with the supplied stepped outline; two-layer FR4, 1.6 mm nominal finished thickness and 1 oz copper.

• Black solder mask, white silkscreen and leaded HASL for this project fabrication variant.

MODXO ApexusNULL is designed to let an original Xbox boot a custom BIOS instead of its factory BIOS. Its RP2040 processor runs Modxo firmware and supplies the BIOS through the Xbox’s LPC connection during startup. Modxo documentation

With suitable BIOS and software, this enables homebrew applications, emulators, custom dashboards and expanded storage support. It is also designed for the YD-RP2040 version of PrometheOS, which supports Modxo hardware. PrometheOS documentation

The board brings that functionality into a compact installation with USB-C programming, a BOOT button, two indicator LEDs, and connectors for displays, RGB lighting and other supported accessories. Those accessory functions depend on the installed firmware and connected hardware.