diff --git a/system/drivers/usb-xhci-bus/usb-xhci-library.zig b/system/drivers/usb-xhci-bus/usb-xhci-library.zig
index feaef0b..656ca98 100644
--- a/system/drivers/usb-xhci-bus/usb-xhci-library.zig
+++ b/system/drivers/usb-xhci-bus/usb-xhci-library.zig
@@ -101,6 +101,7 @@ pub const TrbType = enum(u6) {
 pub const CompletionCode = enum(u8) {
     invalid = 0,
     success = 1,
+    usb_transaction_error = 4,
     short_packet = 13,
     _,
 };
@@ -836,19 +837,31 @@ pub const Controller = struct {
     }
 
     fn addressDeviceCommand(self: *Controller, device: *Device) bool {
-        const physical = self.submitCommand(.{
-            .parameter = device.input_context.physical,
-            .control = trbControl(.address_device, @as(u32, device.slot_id) << 24),
-        });
-        const code = self.awaitCommand(physical) orelse {
-            std.log.info("port {d} setup: Address Device timed out", .{device.port});
-            return false;
-        };
-        if (code != @intFromEnum(CompletionCode.success)) {
-            std.log.info("port {d} setup: Address Device completion code {d}", .{ device.port, code });
-            return false;
+        // Retry on a USB Transaction Error (code 4): a freshly-reset device can
+        // miss the first SET_ADDRESS; re-reset the port and try again (xHCI
+        // 4.6.5). Up to 3 attempts.
+        var attempt: u32 = 0;
+        while (attempt < 3) : (attempt += 1) {
+            const physical = self.submitCommand(.{
+                .parameter = device.input_context.physical,
+                .control = trbControl(.address_device, @as(u32, device.slot_id) << 24),
+            });
+            const code = self.awaitCommand(physical) orelse {
+                std.log.info("port {d} setup: Address Device timed out (attempt {d})", .{ device.port, attempt + 1 });
+                return false;
+            };
+            if (code == @intFromEnum(CompletionCode.success)) return true;
+            std.log.info("port {d} setup: Address Device completion code {d} (attempt {d})", .{ device.port, code, attempt + 1 });
+            if (code != @intFromEnum(CompletionCode.usb_transaction_error)) return false;
+            // Re-reset a root-port device and wait the recovery interval before
+            // retrying. (A device behind a hub is reset through the hub — not
+            // retried here; its port was reset in serviceHubPort.)
+            if (device.parent_slot == 0) {
+                if (!self.resetPort(device.port)) return false;
+                system.sleep(10);
+            } else return false;
         }
-        return true;
+        return false;
     }
 
     /// Reset the port, enable a slot, and address the device on it: after this the
@@ -874,6 +887,11 @@ pub const Controller = struct {
             // (pre-reset reads misreport on real controllers; M20).
             effective_speed = (self.portStatus(port) >> 10) & 0xF;
             if (effective_speed == 0) effective_speed = speed; // defensive: keep the caller's read
+            // USB 2.0 spec 7.1.7.5: a device needs a reset-recovery interval
+            // (TRSTRCY, 10 ms) after reset before it answers SET_ADDRESS.
+            // Addressing immediately gives a USB Transaction Error (code 4) on
+            // real full-speed devices; QEMU tolerates the omission.
+            system.sleep(10);
         }
         const slot_id = self.enableSlot() orelse {
             std.log.info("port {d} setup: Enable Slot failed", .{port});