diff --git a/src/system/libroot/os/arch/ppc/Jamfile b/src/system/libroot/os/arch/ppc/Jamfile
index 7bddfbcf5b..8bbcf87822 100644
--- a/src/system/libroot/os/arch/ppc/Jamfile
+++ b/src/system/libroot/os/arch/ppc/Jamfile
@@ -5,6 +5,8 @@ UseHeaders $(TARGET_PRIVATE_KERNEL_HEADERS) : true ;
 MergeObject os_arch_$(TARGET_ARCH).o :
 	atomic.S
 	byteorder.S
+	compatibility.c	# only here until the places where those functions are used
+					# are fixed
 #	systeminfo.c
 	system_time.S
 	thread.c
diff --git a/src/system/libroot/os/arch/ppc/compatibility.c b/src/system/libroot/os/arch/ppc/compatibility.c
new file mode 100644
index 0000000000..1411ca6560
--- /dev/null
+++ b/src/system/libroot/os/arch/ppc/compatibility.c
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2005, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+
+// This file includes some known R5 syscalls
+// ToDo: maybe they should indeed do something...
+
+#include <SupportDefs.h>
+
+
+int _kset_mon_limit_(int num);
+int _kset_fd_limit_(int num);
+int _kget_cpu_state_(int cpuNum);
+int _kset_cpu_state_(int cpuNum, int state);
+
+
+int
+_kset_mon_limit_(int num)
+{
+	return B_ERROR;
+}
+
+
+int
+_kset_fd_limit_(int num)
+{
+	return B_ERROR;
+}
+
+
+int
+_kget_cpu_state_(int cpuNum)
+{
+	return 1;
+}
+
+
+int
+_kset_cpu_state_(int cpuNum, int state)
+{
+	return state ? B_OK : B_ERROR;
+}
+