Will Whang created an open-source HAT+ for Raspberry Pi 5 that adds a microSD Express card slot, delivering SSD-like performance through PCIe interface. The board includes a WCH CH32V003 RISC-V microcontroller for hotplugging, two Qwiic connectors, and an eject button. Benchmarks show read speeds over 630MB/s, significantly faster than traditional microSD cards. However, microSD Express cards remain expensive ($60 for 256GB) compared to equivalent M.2 NVMe SSDs ($25), making the practical value limited. The design files are available on GitHub under MIT license, though Will won't manufacture it commercially due to cost considerations.
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