diff -r 4a8fed1c0ef6 -r 597aaf25e343 kernel/eka/drivers/usbcsc/d_usbcsc.cpp
--- a/kernel/eka/drivers/usbcsc/d_usbcsc.cpp	Sat Feb 20 00:10:51 2010 +0200
+++ b/kernel/eka/drivers/usbcsc/d_usbcsc.cpp	Fri Mar 12 15:50:11 2010 +0200
@@ -3026,7 +3026,13 @@
 			{
 			dUsbc->ProcessDeviceState(deviceState);
 			// Send Status to EP0 buffer.		
-			dUsbc->iBuffers[dUsbc->iEP0OutBuff].SendEp0StatusPacket(deviceState);
+			// Before the client calls RDevUsbcScClient::FinalizeInterface(),
+			// this function might be called.
+			// So we add a guard for dUsbc->iBuffers
+			if( dUsbc->iBuffers )
+				{
+				dUsbc->iBuffers[dUsbc->iEP0OutBuff].SendEp0StatusPacket(deviceState);
+				}
 			}
 
 		// Only queue if userside is interested