diff --git a/firmware/target/arm/mmu-armv6.S b/firmware/target/arm/mmu-armv6.S
index bb2d8a203f..58e03d6614 100644
--- a/firmware/target/arm/mmu-armv6.S
+++ b/firmware/target/arm/mmu-armv6.S
@@ -25,6 +25,8 @@
 
 /** Cache coherency **/
 
+#if 0 /* unused */
+
 /*
  * Invalidate DCache for this range
  * will do write back
@@ -45,6 +47,8 @@ invalidate_dcache_range:
     bx      lr                      @
     .size   invalidate_dcache_range, .-invalidate_dcache_range
 
+#endif /* unused function */
+
 /*
  * clean DCache for this range
  * forces DCache writeback for the specified range