diff --git a/src/SerialConsole.cpp b/src/SerialConsole.cpp
index 24141be28..fb40bf891 100644
--- a/src/SerialConsole.cpp
+++ b/src/SerialConsole.cpp
@@ -16,6 +16,11 @@
 #ifdef SERIAL_HAS_ON_RECEIVE
 #undef SERIAL_HAS_ON_RECEIVE
 #endif
+// Port is HWCDC only in hardware USB-Serial/JTAG mode. With ARDUINO_USB_MODE=0 it is TinyUSB
+// USBCDC, the PHY is routed away from the USJ peripheral, and isPlugged() would never see a SOF.
+#if defined(ARDUINO_USB_MODE) && ARDUINO_USB_MODE
+#define IS_USB_HWCDC
+#endif
 #include "HWCDC.h"
 #endif
 
@@ -130,8 +135,10 @@ int32_t SerialConsole::runOnce()
     if (hasPendingOutput())
         return delay < 25 ? delay : 25; // 0 continues a budget slice; else short-poll TX drain
     return Port.available() ? delay : INT32_MAX;
-#elif defined(IS_USB_SERIAL)
-    return HWCDC::isPlugged() ? delay : (1000 * 20);
+#elif defined(IS_USB_HWCDC)
+    // isPlugged() is a SOF watchdog that flaps false while USB is fine (#11864), and nothing wakes
+    // this thread on RX, so cap the idle sleep at the rate readStream() already idles at.
+    return HWCDC::isPlugged() ? delay : 250;
 #else
     return delay;
 #endif