diff --git a/libsrc/geos-cbm/system/Makefile b/libsrc/geos-cbm/system/Makefile
index c20b2f393..a39ad6e4c 100644
--- a/libsrc/geos-cbm/system/Makefile
+++ b/libsrc/geos-cbm/system/Makefile
@@ -7,6 +7,7 @@
 
 S_OBJS  +=      ctype.o			\
 		get_ostype.o		\
+		getserialnumber.o	\
 		initdoneio.o		\
 		setdevice.o		\
 		tobasic.o
diff --git a/libsrc/geos-common/system/getserialnumber.s b/libsrc/geos-cbm/system/getserialnumber.s
similarity index 100%
rename from libsrc/geos-common/system/getserialnumber.s
rename to libsrc/geos-cbm/system/getserialnumber.s
diff --git a/libsrc/geos-common/system/Makefile b/libsrc/geos-common/system/Makefile
index 0e711c622..127b2ae1b 100644
--- a/libsrc/geos-common/system/Makefile
+++ b/libsrc/geos-common/system/Makefile
@@ -13,7 +13,6 @@ S_OBJS  +=      callroutine.o		\
 		extzp.o			\
 		firstinit.o		\
 		getrandom.o		\
-		getserialnumber.o	\
 		mainargs.o		\
 		mainloop.o		\
 		oserrlist.o		\