Index: uspace/drv/bus/usb/xhci/hw_struct/context.h
===================================================================
--- uspace/drv/bus/usb/xhci/hw_struct/context.h	(revision 73e5b6249034e0a254d81d99236c5f71740db6f6)
+++ uspace/drv/bus/usb/xhci/hw_struct/context.h	(revision 7428b925cd218f639c5da7dde3d0259a1e078bc3)
@@ -125,7 +125,13 @@
 	uint32_t data [16];
 #define XHCI_INPUT_CTRL_CTX_DROP(ctx, idx) \
-	(assert((idx) > 1 && (idx) < 32), XHCI_DWORD_EXTRACT((ctx).data[0], (idx), (idx)))
+	XHCI_DWORD_EXTRACT((ctx).data[0], (idx), (idx))
+
+#define XHCI_INPUT_CTRL_CTX_DROP_SET(ctx, idx) (ctx).data[0] |= (1 << (idx))
+
 #define XHCI_INPUT_CTRL_CTX_ADD(ctx, idx) \
-	(assert((idx) >= 0 && (idx) < 32), XHCI_DWORD_EXTRACT((ctx).data[1], (idx), (idx)))
+	XHCI_DWORD_EXTRACT((ctx).data[1], (idx), (idx))
+
+#define XHCI_INPUT_CTRL_CTX_ADD_SET(ctx, idx) (ctx).data[1] |= (1 << (idx))
+    
 #define XHCI_INPUT_CTRL_CTX_CONFIG_VALUE(ctx)   XHCI_DWORD_EXTRACT((ctx).data[7],  7,  0)
 #define XHCI_INPUT_CTRL_CTX_IFACE_NUMBER(ctx)   XHCI_DWORD_EXTRACT((ctx).data[7], 15,  8)
@@ -137,5 +143,5 @@
  */
 typedef struct xhci_input_ctx {
-	xhci_input_ctrl_ctx_t ctr_ctx;
+	xhci_input_ctrl_ctx_t ctrl_ctx;
 	xhci_slot_ctx_t slot_ctx;
 	xhci_ep_ctx_t endpoint_ctx [31];