diff --git a/arch/arm/src/rp2040/rp2040_usbdev.c b/arch/arm/src/rp2040/rp2040_usbdev.c
index ceb7a9e965c..470f32567ed 100644
--- a/arch/arm/src/rp2040/rp2040_usbdev.c
+++ b/arch/arm/src/rp2040/rp2040_usbdev.c
@@ -2184,8 +2184,17 @@ int usbdev_register(struct usbdevclass_driver_s *driver)
 
   /* Enable interrupt */
 
-  putreg32(RP2040_USBCTRL_REGS_SIE_CTRL_EP0_INT_1BUF,
-           RP2040_USBCTRL_REGS_SIE_CTRL);
+  /* Use setbits, NOT putreg32: CLASS_BIND above ends with DEV_CONNECT
+   * (composite_bind/cdcacm_bind), which sets SIE_CTRL.PULLUP_EN.  A
+   * wholesale write here clobbers that pull-up microseconds after it was
+   * asserted; enumeration then only succeeds if the host happened to
+   * latch the short pull-up blip and issues a bus reset (whose handler
+   * re-arms the pull-up).  A cold-plugged host port misses the blip and
+   * the device stays disconnected forever.
+   */
+
+  setbits_reg32(RP2040_USBCTRL_REGS_SIE_CTRL_EP0_INT_1BUF,
+                RP2040_USBCTRL_REGS_SIE_CTRL);
   putreg32(RP2040_USBCTRL_REGS_INTR_BUFF_STATUS |
            RP2040_USBCTRL_REGS_INTR_BUS_RESET |
            RP2040_USBCTRL_REGS_INTR_SETUP_REQ,
diff --git a/arch/arm/src/rp23xx/rp23xx_usbdev.c b/arch/arm/src/rp23xx/rp23xx_usbdev.c
index cfece8936bf..357b96eb8d8 100644
--- a/arch/arm/src/rp23xx/rp23xx_usbdev.c
+++ b/arch/arm/src/rp23xx/rp23xx_usbdev.c
@@ -2176,8 +2176,17 @@ int usbdev_register(struct usbdevclass_driver_s *driver)
 
   /* Enable interrupt */
 
-  putreg32(RP23XX_USBCTRL_REGS_SIE_CTRL_EP0_INT_1BUF,
-           RP23XX_USBCTRL_REGS_SIE_CTRL);
+  /* Use setbits, NOT putreg32: CLASS_BIND above ends with DEV_CONNECT
+   * (composite_bind/cdcacm_bind), which sets SIE_CTRL.PULLUP_EN.  A
+   * wholesale write here clobbers that pull-up microseconds after it was
+   * asserted; enumeration then only succeeds if the host happened to
+   * latch the short pull-up blip and issues a bus reset (whose handler
+   * re-arms the pull-up).  A cold-plugged host port misses the blip and
+   * the device stays disconnected forever.
+   */
+
+  setbits_reg32(RP23XX_USBCTRL_REGS_SIE_CTRL_EP0_INT_1BUF,
+                RP23XX_USBCTRL_REGS_SIE_CTRL);
   putreg32(RP23XX_USBCTRL_REGS_INTR_BUFF_STATUS |
            RP23XX_USBCTRL_REGS_INTR_BUS_RESET |
            RP23XX_USBCTRL_REGS_INTR_SETUP_REQ,