diff --git a/base-foc/lib/mk/arm/base.mk b/base-foc/lib/mk/arm/base.mk
new file mode 100644
index 000000000..5d2889686
--- /dev/null
+++ b/base-foc/lib/mk/arm/base.mk
@@ -0,0 +1,3 @@
+include $(REP_DIR)/lib/mk/base.inc
+
+SRC_CC += thread/thread_context_area.cc
diff --git a/base-foc/lib/mk/base.mk b/base-foc/lib/mk/base.inc
similarity index 86%
rename from base-foc/lib/mk/base.mk
rename to base-foc/lib/mk/base.inc
index 915c86331..8f0a09bb4 100644
--- a/base-foc/lib/mk/base.mk
+++ b/base-foc/lib/mk/base.inc
@@ -9,7 +9,7 @@ LIBS += base-common
 SRC_CC += console/log_console.cc
 SRC_CC += env/env.cc env/context_area.cc env/reload_parent_cap.cc \
           env/cap_map_remove.cc env/cap_alloc.cc
-SRC_CC += thread/thread_start.cc thread/thread_context_area.cc
+SRC_CC += thread/thread_start.cc
 
 INC_DIR += $(BASE_DIR)/src/base/env
 
diff --git a/base-foc/lib/mk/exynos5/base.mk b/base-foc/lib/mk/exynos5/base.mk
new file mode 100644
index 000000000..5de464872
--- /dev/null
+++ b/base-foc/lib/mk/exynos5/base.mk
@@ -0,0 +1,3 @@
+include $(REP_DIR)/lib/mk/base.inc
+
+SRC_CC += thread/arndale/thread_context_area.cc
diff --git a/base-foc/lib/mk/x86/base.mk b/base-foc/lib/mk/x86/base.mk
new file mode 100644
index 000000000..5d2889686
--- /dev/null
+++ b/base-foc/lib/mk/x86/base.mk
@@ -0,0 +1,3 @@
+include $(REP_DIR)/lib/mk/base.inc
+
+SRC_CC += thread/thread_context_area.cc
diff --git a/base-foc/src/core/arndale/thread_context_area.cc b/base-foc/src/base/thread/arndale/thread_context_area.cc
similarity index 70%
rename from base-foc/src/core/arndale/thread_context_area.cc
rename to base-foc/src/base/thread/arndale/thread_context_area.cc
index b9c7c2772..9764793d7 100644
--- a/base-foc/src/core/arndale/thread_context_area.cc
+++ b/base-foc/src/base/thread/arndale/thread_context_area.cc
@@ -6,6 +6,10 @@
  * We need to place the context area within core outside the physical memory.
  * Sigma0 maps physical to core-local memory always 1:1 when using
  * SIGMA0_REQ_FPAGE_ANY. Those mappings would interfere with the context area.
+ *
+ * Because the UTCB area of a task resides at the end of the context area and
+ * its address gets calculated by core, the context area in other tasks needs
+ * to be at the same address as in core.
  */
 
 #include <base/native_types.h>
diff --git a/base-foc/src/core/arndale/target.mk b/base-foc/src/core/arndale/target.mk
index 51858401f..4290ec929 100644
--- a/base-foc/src/core/arndale/target.mk
+++ b/base-foc/src/core/arndale/target.mk
@@ -1,5 +1,5 @@
 # override default location of thread context area within core
-vpath thread_context_area.cc $(PRG_DIR)
+vpath thread_context_area.cc $(REP_DIR)/src/base/thread/arndale
 
 include $(PRG_DIR)/../target.inc