Freer requires outct CT_END negociation in both ways before closing down.

module_usb_aud_shared/reboot.xcnot

@@ -8,6 +8,7 @@ int write_sswitch_reg_blind(unsigned coreid, unsigned reg, unsigned data);
 void device_reboot(chanend spare) 
 {
     outct(spare, XS1_CT_END); // have to do this before freeing the chanend
+    inct(spare); // Receive end ct from usb_buffer to close down in both directions
     // Need a spare chanend so we can talk to the pll register
     asm("freer res[%0]"::"r"(spare));
     // Need to tell the mapper we have freed one