diff --git a/kernel/marucoin-mod.cl b/kernel/marucoin-mod.cl
index a5513634..1618efce 100644
--- a/kernel/marucoin-mod.cl
+++ b/kernel/marucoin-mod.cl
@@ -75,7 +75,9 @@ typedef long sph_s64;
 #define SPH_GROESTL_BIG_ENDIAN 0
 #define SPH_CUBEHASH_UNROLL 0
 #define SPH_KECCAK_UNROLL   0
+#if !defined SPH_HAMSI_EXPAND_BIG
 #define SPH_HAMSI_EXPAND_BIG 4
+#endif
 
 #include "blake.cl"
 #include "bmw.cl"
diff --git a/kernel/marucoin-modold.cl b/kernel/marucoin-modold.cl
index c6db8017..83d6e64b 100644
--- a/kernel/marucoin-modold.cl
+++ b/kernel/marucoin-modold.cl
@@ -75,7 +75,9 @@ typedef long sph_s64;
 #define SPH_GROESTL_BIG_ENDIAN 0
 #define SPH_CUBEHASH_UNROLL 0
 #define SPH_KECCAK_UNROLL   0
+#if !defined SPH_HAMSI_EXPAND_BIG
 #define SPH_HAMSI_EXPAND_BIG 4
+#endif
 
 #include "blake.cl"
 #include "bmw.cl"
diff --git a/kernel/marucoin.cl b/kernel/marucoin.cl
index 65263c91..c0bb7753 100644
--- a/kernel/marucoin.cl
+++ b/kernel/marucoin.cl
@@ -74,7 +74,9 @@ typedef long sph_s64;
 #define SPH_GROESTL_BIG_ENDIAN 0
 #define SPH_CUBEHASH_UNROLL 0
 #define SPH_KECCAK_UNROLL   0
-#define SPH_HAMSI_EXPAND_BIG 1
+#if !defined SPH_HAMSI_EXPAND_BIG
+#define SPH_HAMSI_EXPAND_BIG 4
+#endif
 
 #include "blake.cl"
 #include "bmw.cl"
diff --git a/miner.h b/miner.h
index 800eb561..fc753c9e 100644
--- a/miner.h
+++ b/miner.h
@@ -956,6 +956,7 @@ extern bool opt_worktime;
 extern int swork_id;
 extern int opt_tcp_keepalive;
 extern bool opt_incognito;
+extern int opt_hamsi_expand_big;
 
 #if LOCK_TRACKING
 extern pthread_mutex_t lockstat_lock;
diff --git a/ocl.c b/ocl.c
index 8085a6a6..126978dc 100644
--- a/ocl.c
+++ b/ocl.c
@@ -396,7 +396,8 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize, algorithm_t *alg
 	  build_data->patch_bfi = needs_bfi_patch(build_data);
 
 	  set_base_compiler_options(build_data);
-	  append_scrypt_compiler_options(build_data, cgpu->lookup_gap, cgpu->thread_concurrency, algorithm->nfactor);
+    append_scrypt_compiler_options(build_data, cgpu->lookup_gap, cgpu->thread_concurrency, algorithm->nfactor);
+    append_hamsi_compiler_options(build_data, opt_hamsi_expand_big);
 
 		if (!(clState->program = build_opencl_kernel(build_data, filename)))
 			return NULL;
diff --git a/ocl/build_kernel.c b/ocl/build_kernel.c
index 84223e75..a8969d90 100644
--- a/ocl/build_kernel.c
+++ b/ocl/build_kernel.c
@@ -107,6 +107,16 @@ void append_scrypt_compiler_options(build_kernel_data *data, int lookup_gap, uns
   strcat(data->compiler_options, buf);
 }
 
+// TODO: move away, specific
+void append_hamsi_compiler_options(build_kernel_data *data, int expand_big)
+{
+  char buf[255];
+  sprintf(buf, " -D SPH_HAMSI_EXPAND_BIG=%d",
+      expand_big);
+
+  strcat(data->compiler_options, buf);
+}
+
 cl_program build_opencl_kernel(build_kernel_data *data, const char *filename)
 {
   int pl;
diff --git a/ocl/build_kernel.h b/ocl/build_kernel.h
index 5c756533..52c6233a 100644
--- a/ocl/build_kernel.h
+++ b/ocl/build_kernel.h
@@ -27,5 +27,6 @@ cl_program build_opencl_kernel(build_kernel_data *data, const char *filename);
 bool save_opencl_kernel(build_kernel_data *data, cl_program program);
 void set_base_compiler_options(build_kernel_data *data);
 void append_scrypt_compiler_options(build_kernel_data *data, int lookup_gap, unsigned int thread_concurrency, unsigned int nfactor);
+void append_hamsi_compiler_options(build_kernel_data *data, int expand_big);
 
 #endif /* BUILD_KERNEL_H */
diff --git a/sgminer.c b/sgminer.c
index 63737961..72366d08 100644
--- a/sgminer.c
+++ b/sgminer.c
@@ -108,6 +108,7 @@ time_t last_getwork;
 int nDevs;
 int opt_dynamic_interval = 7;
 int opt_g_threads = -1;
+int opt_hamsi_expand_big = 4;
 bool opt_restart = true;
 
 struct list_head scan_devices;
@@ -1343,6 +1344,9 @@ static struct opt_table opt_config_table[] = {
   OPT_WITH_ARG("--lookup-gap",
       set_lookup_gap, NULL, NULL,
       "Set GPU lookup gap for scrypt mining, comma separated"),
+  OPT_WITH_ARG("--hamsi-expand-big",
+      set_int_1_to_10, opt_show_intval, &opt_hamsi_expand_big,
+      "Set SPH_HAMSI_EXPAND_BIG for X13 algorithms (1 or 4 are common)"),
 #ifdef HAVE_CURSES
   OPT_WITHOUT_ARG("--incognito",
       opt_set_bool, &opt_incognito,