diff --git a/tests/test/host/ehci/test_ehci_pipe.c b/tests/test/host/ehci/test_ehci_pipe.c
index 897d9f1a..d7d571e1 100644
--- a/tests/test/host/ehci/test_ehci_pipe.c
+++ b/tests/test/host/ehci/test_ehci_pipe.c
@@ -314,7 +314,7 @@ tusb_descriptor_endpoint_t const desc_ept_iso_in =
     .bLength          = sizeof(tusb_descriptor_endpoint_t),
     .bDescriptorType  = TUSB_DESC_ENDPOINT,
     .bEndpointAddress = 0x83,
-    .bmAttributes     = { .xfer = TUSB_XFER_BULK },
+    .bmAttributes     = { .xfer = TUSB_XFER_ISOCHRONOUS },
     .wMaxPacketSize   = 1024,
     .bInterval        = 1
 };
diff --git a/tinyusb/host/ehci/ehci.c b/tinyusb/host/ehci/ehci.c
index 8bae98ca..94c65924 100644
--- a/tinyusb/host/ehci/ehci.c
+++ b/tinyusb/host/ehci/ehci.c
@@ -348,6 +348,9 @@ pipe_handle_t hcd_pipe_open(uint8_t dev_addr, tusb_descriptor_endpoint_t const *
 {
   pipe_handle_t const null_handle = { .dev_addr = 0, .xfer_type = 0, .index = 0 };
 
+  if (p_endpoint_desc->bmAttributes.xfer == TUSB_XFER_ISOCHRONOUS)
+    return null_handle; // TODO not support ISO yet
+
   //------------- find a free queue head -------------//
   uint8_t index=0;
   while( index<EHCI_MAX_QHD && ehci_data.device[dev_addr].qhd[index].used )
@@ -378,8 +381,6 @@ pipe_handle_t hcd_pipe_open(uint8_t dev_addr, tusb_descriptor_endpoint_t const *
   list_head->next.type = EHCI_QUEUE_ELEMENT_QHD;
 
   return (pipe_handle_t) { .dev_addr = dev_addr, .xfer_type = p_endpoint_desc->bmAttributes.xfer, .index = index};
-
-//  return null_handle;
 }
 
 //--------------------------------------------------------------------+