diff --git a/system/drivers/usb-xhci-bus/usb-xhci-library.zig b/system/drivers/usb-xhci-bus/usb-xhci-library.zig
index c69ecff..544e766 100644
--- a/system/drivers/usb-xhci-bus/usb-xhci-library.zig
+++ b/system/drivers/usb-xhci-bus/usb-xhci-library.zig
@@ -807,6 +807,15 @@ pub const Controller = struct {
     /// MPS0; QEMU forgives it — the classic full-speed-mouse-on-real-hardware
     /// failure (M20).
     fn refreshMaxPacketSize0(self: *Controller, device: *Device) bool {
+        // SuperSpeed (and above) fix EP0's max packet size at 512, and encode
+        // bMaxPacketSize0 as an EXPONENT (9 = 2^9 = 512), not a literal size —
+        // the default is already correct and byte 7 must NOT be read as a size.
+        // Only full/low/high speed carry a literal 8/16/32/64 that can differ
+        // from the speed default and need this correction. (Reading the SS
+        // exponent as a size set EP0 to 9 bytes and broke every following
+        // transfer — a SuperSpeed hub failing to enumerate on real hardware.)
+        if (device.speed >= 4) return true;
+
         var head: [8]u8 = undefined;
         const request = usb_abi.getDescriptor(.device, 0, 0, 8);
         if (!self.controlTransfer(device, request, head[0..], true)) return false;