diff --git a/hw/bsp/ra/family.c b/hw/bsp/ra/family.c
index b78fdedc7..096f0d0ff 100644
--- a/hw/bsp/ra/family.c
+++ b/hw/bsp/ra/family.c
@@ -92,6 +92,10 @@ const bsp_interrupt_event_t g_interrupt_event_link_select[BSP_ICU_VECTOR_MAX_ENT
 //--------------------------------------------------------------------+
 
 void board_init(void) {
+  // Enable global interrupts in CPSR register since board with bootloader such as Arduino Uno R4
+  // can transfer CPU control with CPSR.I bit set to 0 (disable IRQ)
+  __enable_irq();
+
   /* Configure pins. */
   R_IOPORT_Open(&port_ctrl, &family_pin_cfg);
 
diff --git a/src/portable/renesas/rusb2/dcd_rusb2.c b/src/portable/renesas/rusb2/dcd_rusb2.c
index 9383923bd..37fd93497 100644
--- a/src/portable/renesas/rusb2/dcd_rusb2.c
+++ b/src/portable/renesas/rusb2/dcd_rusb2.c
@@ -740,6 +740,7 @@ void dcd_init(uint8_t rhport)
   rusb->BEMPENB = 1;
   rusb->BRDYENB = 1;
 
+  // If VBUS (detect) pin is not used, application need to call tud_connect() manually after tud_init()
   if (rusb->INTSTS0_b.VBSTS) {
     dcd_connect(rhport);
   }