diff --git a/core/embed/trezorhal/stm32f4/usb.c b/core/embed/trezorhal/stm32f4/usb.c
index 8efc0f5fef..9249c4b9e8 100644
--- a/core/embed/trezorhal/stm32f4/usb.c
+++ b/core/embed/trezorhal/stm32f4/usb.c
@@ -487,12 +487,10 @@ static uint8_t usb_class_setup(USBD_HandleTypeDef *dev,
     }
     switch (usb_ifaces[req->wIndex].type) {
       case USB_IFACE_TYPE_HID:
-        wait_random();
         return usb_hid_class_setup(dev, &usb_ifaces[req->wIndex].hid, req);
       case USB_IFACE_TYPE_VCP:
         return usb_vcp_class_setup(dev, &usb_ifaces[req->wIndex].vcp, req);
       case USB_IFACE_TYPE_WEBUSB:
-        wait_random();
         return usb_webusb_class_setup(dev, &usb_ifaces[req->wIndex].webusb,
                                       req);
       default:
@@ -511,14 +509,12 @@ static uint8_t usb_class_data_in(USBD_HandleTypeDef *dev, uint8_t ep_num) {
   for (int i = 0; i < USBD_MAX_NUM_INTERFACES; i++) {
     switch (usb_ifaces[i].type) {
       case USB_IFACE_TYPE_HID:
-        wait_random();
         usb_hid_class_data_in(dev, &usb_ifaces[i].hid, ep_num);
         break;
       case USB_IFACE_TYPE_VCP:
         usb_vcp_class_data_in(dev, &usb_ifaces[i].vcp, ep_num);
         break;
       case USB_IFACE_TYPE_WEBUSB:
-        wait_random();
         usb_webusb_class_data_in(dev, &usb_ifaces[i].webusb, ep_num);
         break;
       default:
@@ -535,14 +531,12 @@ static uint8_t usb_class_data_out(USBD_HandleTypeDef *dev, uint8_t ep_num) {
   for (int i = 0; i < USBD_MAX_NUM_INTERFACES; i++) {
     switch (usb_ifaces[i].type) {
       case USB_IFACE_TYPE_HID:
-        wait_random();
         usb_hid_class_data_out(dev, &usb_ifaces[i].hid, ep_num);
         break;
       case USB_IFACE_TYPE_VCP:
         usb_vcp_class_data_out(dev, &usb_ifaces[i].vcp, ep_num);
         break;
       case USB_IFACE_TYPE_WEBUSB:
-        wait_random();
         usb_webusb_class_data_out(dev, &usb_ifaces[i].webusb, ep_num);
         break;
       default:
diff --git a/core/embed/trezorhal/stm32f4/usb_hid-impl.h b/core/embed/trezorhal/stm32f4/usb_hid-impl.h
index d08be2a78d..349822287f 100644
--- a/core/embed/trezorhal/stm32f4/usb_hid-impl.h
+++ b/core/embed/trezorhal/stm32f4/usb_hid-impl.h
@@ -267,6 +267,8 @@ static void usb_hid_class_deinit(USBD_HandleTypeDef *dev,
 
 static int usb_hid_class_setup(USBD_HandleTypeDef *dev, usb_hid_state_t *state,
                                USBD_SetupReqTypedef *req) {
+  wait_random();
+
   switch (req->bmRequest & USB_REQ_TYPE_MASK) {
     // Class request
     case USB_REQ_TYPE_CLASS:
@@ -340,6 +342,7 @@ static int usb_hid_class_setup(USBD_HandleTypeDef *dev, usb_hid_state_t *state,
 static void usb_hid_class_data_in(USBD_HandleTypeDef *dev,
                                   usb_hid_state_t *state, uint8_t ep_num) {
   if ((ep_num | USB_EP_DIR_IN) == state->ep_in) {
+    wait_random();
     state->ep_in_is_idle = 1;
   }
 }
@@ -347,6 +350,7 @@ static void usb_hid_class_data_in(USBD_HandleTypeDef *dev,
 static void usb_hid_class_data_out(USBD_HandleTypeDef *dev,
                                    usb_hid_state_t *state, uint8_t ep_num) {
   if (ep_num == state->ep_out) {
+    wait_random();
     // Save the report length to indicate we have read something, but don't
     // schedule next reading until user reads this one
     state->last_read_len = USBD_LL_GetRxDataSize(dev, ep_num);
diff --git a/core/embed/trezorhal/stm32f4/usb_webusb-impl.h b/core/embed/trezorhal/stm32f4/usb_webusb-impl.h
index cfc08d4fa2..3ffe4589e8 100644
--- a/core/embed/trezorhal/stm32f4/usb_webusb-impl.h
+++ b/core/embed/trezorhal/stm32f4/usb_webusb-impl.h
@@ -243,6 +243,8 @@ static int usb_webusb_class_setup(USBD_HandleTypeDef *dev,
     return USBD_OK;
   }
 
+  wait_random();
+
   switch (req->bRequest) {
     case USB_REQ_SET_INTERFACE:
       state->alt_setting = req->wValue;
@@ -263,6 +265,7 @@ static void usb_webusb_class_data_in(USBD_HandleTypeDef *dev,
                                      usb_webusb_state_t *state,
                                      uint8_t ep_num) {
   if ((ep_num | USB_EP_DIR_IN) == state->ep_in) {
+    wait_random();
     state->ep_in_is_idle = 1;
   }
 }
@@ -271,6 +274,7 @@ static void usb_webusb_class_data_out(USBD_HandleTypeDef *dev,
                                       usb_webusb_state_t *state,
                                       uint8_t ep_num) {
   if (ep_num == state->ep_out) {
+    wait_random();
     // Save the report length to indicate we have read something, but don't
     // schedule next reading until user reads this one
     state->last_read_len = USBD_LL_GetRxDataSize(dev, ep_num);