M.2 is just a different connector style. Electrically, it is absolutely identical regarding the PCIe signals. Power is a bit different. You don't get +12V, you don't get standby power, and you can't pull as much current from the +3.3V line as from a regular slot.But what I wonder, is where the compatibility issues are? Like is this something where if a drive works in one HAT it works on all Pi HATs? Or is it something where most NVMe HATs use the same M.2 to the PCIe chipset? I’m not even sure how different a PCIe style M.2 slot is from PCIe tbh.
If you have a simple hat where the M.2 slot is just wired directly to the Pi's PCIe connector it only depends on the NVME SSD. The hat itself is only a set of wires then.
However, on some hats there are PCIe bridges than connect multiple devices to the PI's only PCIe bus. This is a whole different story of additional driver code needed to handle the PCIe bridge, bandwidth issues (the bandwidth doesn't become magically more, it's shared between devices) and other compatibility quirks.
Statistics: Posted by fchk — Sun Dec 28, 2025 9:10 am