Index: kernel/generic/include/ipc/sysipc.h
===================================================================
--- kernel/generic/include/ipc/sysipc.h	(revision d99c1d2ba8c7b2c687d430f2e9fd237046606545)
+++ kernel/generic/include/ipc/sysipc.h	(revision 46416ab46665e2b77b325c73f9e704fe7bd5bf83)
@@ -57,5 +57,5 @@
 unative_t sys_ipc_forward_slow(unative_t callid, unative_t phoneid,
     ipc_data_t *data, int mode);
-unative_t sys_ipc_hangup(int phoneid);
+unative_t sys_ipc_hangup(unative_t phoneid);
 unative_t sys_ipc_register_irq(inr_t inr, devno_t devno, unative_t method,
     irq_code_t *ucode);