diff --git a/kernel/alexkarnew.cl b/kernel/alexkarnew.cl
index 757e8114..43486c3e 100644
--- a/kernel/alexkarnew.cl
+++ b/kernel/alexkarnew.cl
@@ -28,6 +28,11 @@
  * online backup system.
  */
 
+/* Backwards compatibility, if NFACTOR not defined, default to 1024 scrypt */
+#ifndef NFACTOR
+#define NFACTOR 1024
+#endif
+
 __constant uint ES[2] = { 0x00FF00FF, 0xFF00FF00 };
 __constant uint K[] = {
 	0x428a2f98U,
@@ -761,7 +766,7 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 	uint CO=rotl(x,3U);
 	uint CO_tmp=rotl(xSIZE,3U);
 
-	for(uint y=0; y<1024/LOOKUP_GAP; ++y, CO+=CO_tmp)
+	for(uint y=0; y<NFACTOR/LOOKUP_GAP; ++y, CO+=CO_tmp)
 	{
 		uint CO_reg=CO;
 #pragma unroll
@@ -775,20 +780,20 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 
 #if (LOOKUP_GAP != 1) && (LOOKUP_GAP != 2) && (LOOKUP_GAP != 4) && (LOOKUP_GAP != 8)
 	{
-		uint y = (1024/LOOKUP_GAP);
+		uint y = (NFACTOR/LOOKUP_GAP);
 		CO=CO_tmp+rotl(y*xSIZE,3U);
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z, ++CO)
 			lookup[CO] = X[z];
-		for(uint i=0; i<1024%LOOKUP_GAP; ++i)
+		for(uint i=0; i<NFACTOR%LOOKUP_GAP; ++i)
 			salsa(X); 
 	}
 #endif
 
-	for (uint i=0; i<1024; ++i) 
+	for (uint i=0; i<NFACTOR; ++i) 
 	{
 		uint4 V[8];
-		uint j = X[7].x & K[85];
+		uint j = X[7].x & (NFACTOR-1);
 		uint y = (j/LOOKUP_GAP);
 		uint CO_reg=CO_tmp+rotl(xSIZE*y,3U);
 
diff --git a/kernel/alexkarold.cl b/kernel/alexkarold.cl
index 9c3c1b7b..0ca85558 100644
--- a/kernel/alexkarold.cl
+++ b/kernel/alexkarold.cl
@@ -28,6 +28,11 @@
  * online backup system.
  */
 
+/* Backwards compatibility, if NFACTOR not defined, default to 1024 scrypt */
+#ifndef NFACTOR
+#define NFACTOR 1024
+#endif
+
 __constant uint ES[2] = { 0x00FF00FF, 0xFF00FF00 };
 __constant uint K[] = {
 	0x428a2f98U,
@@ -761,7 +766,7 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 	uint CO_tmp=xSIZE<<3U;
 	uint CO_tmp2=x<<3U;
 
-	for(uint y=0; y<1024/LOOKUP_GAP; ++y)
+	for(uint y=0; y<NFACTOR/LOOKUP_GAP; ++y)
 	{
 		uint CO=y*CO_tmp+CO_tmp2;
 #pragma unroll
@@ -773,19 +778,19 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 	
 #if (LOOKUP_GAP != 1) && (LOOKUP_GAP != 2) && (LOOKUP_GAP != 4) && (LOOKUP_GAP != 8)
 	{
-		uint y = (1024/LOOKUP_GAP);
+		uint y = (NFACTOR/LOOKUP_GAP);
 		uint CO=y*CO_tmp+CO_tmp2;
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
 			lookup[CO] = X[z];
-		for(uint i=0; i<1024%LOOKUP_GAP; ++i)
+		for(uint i=0; i<NFACTOR%LOOKUP_GAP; ++i)
 			salsa(X); 
 	}
 #endif
-	for (uint i=0; i<1024; ++i) 
+	for (uint i=0; i<NFACTOR; ++i) 
 	{
 		uint4 V[8];
-		uint j = X[7].x & K[85];
+		uint j = X[7].x & (NFACTOR-1);
 		uint y = (j/LOOKUP_GAP);
 		uint CO=y*CO_tmp+CO_tmp2;
 #pragma unroll
diff --git a/kernel/ckolivas.cl b/kernel/ckolivas.cl
index 6b264bc7..b88206b7 100644
--- a/kernel/ckolivas.cl
+++ b/kernel/ckolivas.cl
@@ -28,6 +28,11 @@
  * online backup system.
  */
 
+/* Backwards compatibility, if NFACTOR not defined, default to 1024 scrypt */
+#ifndef NFACTOR
+#define NFACTOR 1024
+#endif
+
 __constant uint ES[2] = { 0x00FF00FF, 0xFF00FF00 };
 __constant uint K[] = {
 	0x428a2f98U,
@@ -759,11 +764,11 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 {
 	shittify(X);
 	const uint zSIZE = 8;
-	const uint ySIZE = (1024/LOOKUP_GAP+(1024%LOOKUP_GAP>0));
+	const uint ySIZE = (NFACTOR/LOOKUP_GAP+(NFACTOR%LOOKUP_GAP>0));
 	const uint xSIZE = CONCURRENT_THREADS;
 	uint x = get_global_id(0)%xSIZE;
 
-	for(uint y=0; y<1024/LOOKUP_GAP; ++y)
+	for(uint y=0; y<NFACTOR/LOOKUP_GAP; ++y)
 	{
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
@@ -773,18 +778,18 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 	}
 #if (LOOKUP_GAP != 1) && (LOOKUP_GAP != 2) && (LOOKUP_GAP != 4) && (LOOKUP_GAP != 8)
 	{
-		uint y = (1024/LOOKUP_GAP);
+		uint y = (NFACTOR/LOOKUP_GAP);
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
 			lookup[CO] = X[z];
-		for(uint i=0; i<1024%LOOKUP_GAP; ++i)
+		for(uint i=0; i<NFACTOR%LOOKUP_GAP; ++i)
 			salsa(X); 
 	}
 #endif
-	for (uint i=0; i<1024; ++i) 
+	for (uint i=0; i<NFACTOR; ++i) 
 	{
 		uint4 V[8];
-		uint j = X[7].x & K[85];
+		uint j = X[7].x & (NFACTOR-1);
 		uint y = (j/LOOKUP_GAP);
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
diff --git a/kernel/psw.cl b/kernel/psw.cl
index acd805e0..2c8387f9 100644
--- a/kernel/psw.cl
+++ b/kernel/psw.cl
@@ -29,6 +29,11 @@
  * online backup system.
  */
 
+/* Backwards compatibility, if NFACTOR not defined, default to 1024 scrypt */
+#ifndef NFACTOR
+#define NFACTOR 1024
+#endif
+
 __constant uint ES[2] = { 0x00FF00FF, 0xFF00FF00 };
 __constant uint K[] = {
 	0x428a2f98U,
@@ -698,11 +703,11 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 {
 	shittify(X);
 	const uint zSIZE = 8;
-	const uint ySIZE = (1024/LOOKUP_GAP+(1024%LOOKUP_GAP>0));
+	const uint ySIZE = (NFACTOR/LOOKUP_GAP+(NFACTOR%LOOKUP_GAP>0));
 	const uint xSIZE = CONCURRENT_THREADS;
 	uint x = get_global_id(0)%xSIZE;
 
-	for(uint y=0; y<1024/LOOKUP_GAP; ++y)
+	for(uint y=0; y<NFACTOR/LOOKUP_GAP; ++y)
 	{
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
@@ -712,18 +717,18 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 	}
 #if (LOOKUP_GAP != 1) && (LOOKUP_GAP != 2) && (LOOKUP_GAP != 4) && (LOOKUP_GAP != 8)
 	{
-		uint y = (1024/LOOKUP_GAP);
+		uint y = (NFACTOR/LOOKUP_GAP);
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
 			lookup[CO] = X[z];
-		for(uint i=0; i<1024%LOOKUP_GAP; ++i)
+		for(uint i=0; i<NFACTOR%LOOKUP_GAP; ++i)
 			salsa(X); 
 	}
 #endif
-	for (uint i=0; i<1024; ++i) 
+	for (uint i=0; i<NFACTOR; ++i) 
 	{
 		uint4 V[8];
-		uint j = X[7].x & K[85];
+		uint j = X[7].x & (NFACTOR-1);
 		uint y = (j/LOOKUP_GAP);
 #pragma unroll
 		for(uint z=0; z<zSIZE; ++z)
diff --git a/kernel/zuikkis.cl b/kernel/zuikkis.cl
index fb06f722..cb6660c1 100644
--- a/kernel/zuikkis.cl
+++ b/kernel/zuikkis.cl
@@ -28,6 +28,11 @@
  * online backup system.
  */
 
+/* Backwards compatibility, if NFACTOR not defined, default to 1024 scrypt */
+#ifndef NFACTOR
+#define NFACTOR 1024
+#endif
+
 __constant uint ES[2] = { 0x00FF00FF, 0xFF00FF00 };
 __constant uint K[] = {
 	0x428a2f98U,
@@ -759,11 +764,11 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 {
 	shittify(X);
 	const uint zSIZE = 8;
-	const uint ySIZE = (1024/LOOKUP_GAP+(1024%LOOKUP_GAP>0));
+	const uint ySIZE = (NFACTOR/LOOKUP_GAP+(NFACTOR%LOOKUP_GAP>0));
 	const uint xSIZE = CONCURRENT_THREADS;
 	uint x = get_global_id(0)%xSIZE;
 
-	for(uint y=0; y<1024/LOOKUP_GAP; ++y)
+	for(uint y=0; y<(NFACTOR/LOOKUP_GAP); ++y)
 	{
 
 		for(uint z=0; z<zSIZE; ++z)
@@ -771,9 +776,9 @@ void scrypt_core(uint4 X[8], __global uint4*restrict lookup)
 		for(uint i=0; i<LOOKUP_GAP; ++i) 
 			salsa(X);
 	}
-	for (uint i=0; i<1024; ++i) 
+	for (uint i=0; i<NFACTOR; ++i) 
 	{
-		uint j = X[7].x & K[85];
+		uint j = X[7].x & (NFACTOR-1);
 		uint y = (j/LOOKUP_GAP);
 
 		if (j&1)
@@ -823,11 +828,11 @@ const uint4 midstate0, const uint4 midstate16, const uint target)
 	{
 		pad0 = tstate0;
 		pad1 = tstate1;
-		X[i<<1 ] = ostate0;
-		X[(i<<1)+1] = ostate1;
+		X[i*2 ] = ostate0;
+		X[i*2+1] = ostate1;
 
 		SHA256(&pad0,&pad1, data, (uint4)(i+1,K[84],0,0), (uint4)(0,0,0,0), (uint4)(0,0,0, K[87]));
-		SHA256(X+(i<<1),X+(i<<1)+1, pad0, pad1, (uint4)(K[84], 0U, 0U, 0U), (uint4)(0U, 0U, 0U, K[88]));
+		SHA256(X+i*2,X+i*2+1, pad0, pad1, (uint4)(K[84], 0U, 0U, 0U), (uint4)(0U, 0U, 0U, K[88]));
 	}
 	scrypt_core(X,padcache);
 	SHA256(&tmp0,&tmp1, X[0], X[1], X[2], X[3]);
diff --git a/miner.h b/miner.h
index b7e4ef1f..589bed5f 100644
--- a/miner.h
+++ b/miner.h
@@ -1018,6 +1018,7 @@ extern bool fulltest(const unsigned char *hash, const unsigned char *target);
 extern int opt_queue;
 extern int opt_scantime;
 extern int opt_expiry;
+extern int opt_nfactor;
 
 extern cglock_t control_lock;
 extern pthread_mutex_t hash_lock;
diff --git a/ocl.c b/ocl.c
index 5bdca3d6..f128636e 100644
--- a/ocl.c
+++ b/ocl.c
@@ -225,6 +225,7 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	cl_uint numPlatforms;
 	cl_uint numDevices;
 	cl_int status;
+	int nfactor = (1<<opt_nfactor);
 
 	status = clGetPlatformIDs(0, NULL, &numPlatforms);
 	if (status != CL_SUCCESS) {
@@ -481,7 +482,7 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	if (!cgpu->opt_tc) {
 		unsigned int sixtyfours;
 
-		sixtyfours =  cgpu->max_alloc / 131072 / 64 - 1;
+		sixtyfours =  cgpu->max_alloc / 131072 / 64 / (nfactor/1024)- 1;
 		cgpu->thread_concurrency = sixtyfours * 64;
 		if (cgpu->shaders && cgpu->thread_concurrency > cgpu->shaders) {
 			cgpu->thread_concurrency -= cgpu->thread_concurrency % cgpu->shaders;
@@ -521,7 +522,7 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	if (clState->goffset)
 		strcat(binaryfilename, "g");
 
-	sprintf(numbuf, "lg%utc%u", cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency);
+	sprintf(numbuf, "lg%utc%un%u", cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency,opt_nfactor);
 	strcat(binaryfilename, numbuf);
 
 	sprintf(numbuf, "w%d", (int)clState->wsize);
@@ -587,8 +588,8 @@ build:
 	/* create a cl program executable for all the devices specified */
 	char *CompilerOptions = (char *)calloc(1, 256);
 
-	sprintf(CompilerOptions, "-D LOOKUP_GAP=%d -D CONCURRENT_THREADS=%d -D WORKSIZE=%d",
-			cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency, (int)clState->wsize);
+	sprintf(CompilerOptions, "-D LOOKUP_GAP=%d -D CONCURRENT_THREADS=%d -D WORKSIZE=%d -D NFACTOR=%d",
+			cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency, (int)clState->wsize,(unsigned int)nfactor);
 
 	applog(LOG_DEBUG, "Setting worksize to %d", (int)(clState->wsize));
 	if (clState->vwidth > 1)
@@ -777,7 +778,7 @@ built:
 		return NULL;
 	}
 
-	size_t ipt = (1024 / cgpu->lookup_gap + (1024 % cgpu->lookup_gap > 0));
+	size_t ipt = (nfactor / cgpu->lookup_gap + (nfactor % cgpu->lookup_gap > 0));
 	size_t bufsize = 128 * ipt * cgpu->thread_concurrency;
 
 	/* Use the max alloc value which has been rounded to a power of
diff --git a/scrypt.c b/scrypt.c
index d135a72d..b2cc005d 100644
--- a/scrypt.c
+++ b/scrypt.c
@@ -356,7 +356,7 @@ salsa20_8(uint32_t B[16], const uint32_t Bx[16])
 /* cpu and memory intensive function to transform a 80 byte buffer into a 32 byte output
    scratchpad size needs to be at least 63 + (128 * r * p) + (256 * r + 64) + (128 * r * N) bytes
  */
-static void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_t *ostate)
+static void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_t *ostate, const cl_uint n)
 {
 	uint32_t * V;
 	uint32_t X[32];
@@ -370,7 +370,7 @@ static void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint
 
 	PBKDF2_SHA256_80_128(input, X);
 
-	for (i = 0; i < 1024; i += 2) {
+	for (i = 0; i < n; i += 2) {
 		memcpy(&V[i * 32], X, 128);
 
 		salsa20_8(&X[0], &X[16]);
@@ -381,8 +381,8 @@ static void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint
 		salsa20_8(&X[0], &X[16]);
 		salsa20_8(&X[16], &X[0]);
 	}
-	for (i = 0; i < 1024; i += 2) {
-		j = X[16] & 1023;
+	for (i = 0; i < n; i += 2) {
+		j = X[16] & (n-1);
 		p2 = (uint64_t *)(&V[j * 32]);
 		for(k = 0; k < 16; k++)
 			p1[k] ^= p2[k];
@@ -390,7 +390,7 @@ static void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint
 		salsa20_8(&X[0], &X[16]);
 		salsa20_8(&X[16], &X[0]);
 
-		j = X[16] & 1023;
+		j = X[16] & (n-1);
 		p2 = (uint64_t *)(&V[j * 32]);
 		for(k = 0; k < 16; k++)
 			p1[k] ^= p2[k];
@@ -403,7 +403,8 @@ static void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint
 }
 
 /* 131583 rounded up to 4 byte alignment */
-#define SCRATCHBUF_SIZE	(131584)
+//#define SCRATCHBUF_SIZE (131584)
+//#define SCRATCHBUF_SIZE (262207)
 
 void scrypt_regenhash(struct work *work)
 {
@@ -411,17 +412,19 @@ void scrypt_regenhash(struct work *work)
 	char *scratchbuf;
 	uint32_t *nonce = (uint32_t *)(work->data + 76);
 	uint32_t *ohash = (uint32_t *)(work->hash);
-
+ 	
 	be32enc_vect(data, (const uint32_t *)work->data, 19);
 	data[19] = htobe32(*nonce);
-	scratchbuf = (char *)alloca(SCRATCHBUF_SIZE);
-	scrypt_1024_1_1_256_sp(data, scratchbuf, ohash);
+	//scratchbuf = alloca(SCRATCHBUF_SIZE);
+	scratchbuf = (char *)alloca((1 << opt_nfactor) * 128 + 512);
+	scrypt_1024_1_1_256_sp(data, scratchbuf, ohash, (1 << opt_nfactor));
 	flip32(ohash, ohash);
 }
 
 static const uint32_t diff1targ = 0x0000ffff;
 
 /* Used externally as confirmation of correct OCL code */
+/*
 int scrypt_test(unsigned char *pdata, const unsigned char *ptarget, uint32_t nonce)
 {
 	uint32_t tmp_hash7, Htarg = le32toh(((const uint32_t *)ptarget)[7]);
@@ -489,3 +492,4 @@ bool scanhash_scrypt(struct thr_info *thr, const unsigned char __maybe_unused *p
 	free(scratchbuf);;
 	return ret;
 }
+*/
diff --git a/sgminer.c b/sgminer.c
index 98e4051c..f16026e4 100644
--- a/sgminer.c
+++ b/sgminer.c
@@ -92,6 +92,7 @@ int opt_log_interval = 5;
 int opt_queue = 1;
 int opt_scantime = 7;
 int opt_expiry = 28;
+int opt_nfactor = 11;
 static const bool opt_time = true;
 unsigned long long global_hashrate;
 unsigned long global_quota_gcd = 1;
@@ -1105,6 +1106,9 @@ static struct opt_table opt_config_table[] = {
 			opt_set_bool, &opt_compact,
 			"Use compact display without per device statistics"),
 #endif
+	OPT_WITH_ARG("--nfactor",
+		     set_int_0_to_9999, opt_show_intval, &opt_nfactor,
+		     "Set scrypt nfactor, default: 10. Currently use 11 for vertcoin!"),
 	OPT_WITHOUT_ARG("--debug|-D",
 		     enable_debug, &opt_debug,
 		     "Enable debug output"),