diff --git a/target/linux/ramips/image/lzma-loader/src/head.S b/target/linux/ramips/image/lzma-loader/src/head.S
index 543996a0da..47a7c9bd63 100644
--- a/target/linux/ramips/image/lzma-loader/src/head.S
+++ b/target/linux/ramips/image/lzma-loader/src/head.S
@@ -109,6 +109,9 @@ __bss_check:
 	/* Setup new "C" stack */
 	la	sp, _stack
 
+	/* reserve stack space for a0-a3 registers */
+	subu	sp, 16
+
 	/* jump to the decompressor routine */
 	la	t0, loader_main
 	jr	t0