diff --git a/src/class/usbtmc/usbtmc_device.c b/src/class/usbtmc/usbtmc_device.c
index 92d8d34ef..abe26ced3 100644
--- a/src/class/usbtmc/usbtmc_device.c
+++ b/src/class/usbtmc/usbtmc_device.c
@@ -263,17 +263,19 @@ void usbtmcd_init_cb(void)
 bool usbtmcd_open_cb(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_length)
 {
   (void)rhport;
-  TU_ASSERT(usbtmc_state.state == STATE_CLOSED);
   uint8_t const * p_desc;
   uint8_t found_endpoints = 0;
 
+  TU_VERIFY(itf_desc->bInterfaceClass    == TUD_USBTMC_APP_CLASS);
+  TU_VERIFY(itf_desc->bInterfaceSubClass == TUD_USBTMC_APP_SUBCLASS);
+
 #ifndef NDEBUG
-  TU_ASSERT(itf_desc->bInterfaceClass == TUD_USBTMC_APP_CLASS);
-  TU_ASSERT(itf_desc->bInterfaceSubClass == TUD_USBTMC_APP_SUBCLASS);
   // Only 2 or 3 endpoints are allowed for USBTMC.
   TU_ASSERT((itf_desc->bNumEndpoints == 2) || (itf_desc->bNumEndpoints ==3));
 #endif
 
+  TU_ASSERT(usbtmc_state.state == STATE_CLOSED);
+
   // Interface
   (*p_length) = 0u;
   p_desc = (uint8_t const *) itf_desc;