MrCART 128 Brings Huge Storage and Expansion Audio to Nintendo Virtual Boy

The new MrCART 128 multicart upgrades the Nintendo Virtual Boy with 128 Mbit flash capacity, microSD folder organization, and ESSound stereo MP3 and WAV playback.

Nintendo's famously short-lived Virtual Boy continues to receive better hardware support three decades after its commercial death, with preorders opening for the new MrCART 128 multicart. Designed by original MrCART creator Mr Flower and offered through Kevin Mellott, the upgraded cartridge dramatically expands on earlier versions. Flash capacity increases from 32 Mbit to 128 Mbit, equivalent to 16MB, allowing support for Virtual Boy ROM images up to that size. Flashing is also claimed to be as much as three times faster, while games can now be organised into folders and subfolders on microSD storage. The most interesting addition is ESSound. By using the Virtual Boy's expansion address space, compatible homebrew software can play stereo MP3 music and WAV sound effects directly from microSD while simultaneously retaining the console's native VSU audio. Developers can control playback, looping, volume and stereo balance, potentially enabling sampled speech, full-quality soundtracks and effects well beyond what original Virtual Boy games normally offered. The cartridge includes nvSRAM for saves, firmware updates from microSD and an ARM-based system-on-chip inside an anodised aluminium shell. MrCART 128 costs $235, comes in black or red, and is expected to ship before the end of 2026.