This project provides an open-source breakout board that dramatically expands the internal I/O of the MLLSE M2 Air mini PC (PCB MX-GB07 V100). By repurposing the onboard M.2 slot, unused SATA header, and Wi-Fi PCIe lanes, the board adds two full-size M.2 Key-B SATA slots and one M.2 Key-M PCIe x1 slot.

An onboard FR9889-based DC-DC converter generates a stable 3.3 V from the system’s 12 V rail to power all three devices, enabling multi-drive NAS, NVR, and homelab builds in an ultra-compact x86 system.

Difficulty: Advanced. To access the PCIe bus, the factory Wi-Fi module must be removed using a hot-air rework station and replaced with a fine-pitch FPC connector. This procedure is not trivial and carries a real risk of damaging the motherboard, but unlocks full PCIe expansion and is well worth it for experienced builders.

Important manufacturing note: the PCB must be produced with a thickness of 0.8 mm for correct mechanical fit and connector alignment.