Unless something is particularly unique with this HiFive revision you can use PCIe SSDs it just looks like this one is relatively lane starved and you'll need t

Unless something is particularly unique with this HiFive revision you can use PCIe SSDs it just looks like this one is relatively lane starved and you'll need to eat the PCIe slot to do so (it's a x16 slot physically but only x4 in terms of actual wired lanes). The E-keyed slot is listed as SDIO, but even if it had PCIe wired up it'd be a max of x2 lanes.