diff --git a/libfprint/aeslib.c b/libfprint/aeslib.c
index e93e06f..aa8571e 100644
--- a/libfprint/aeslib.c
+++ b/libfprint/aeslib.c
@@ -93,3 +93,18 @@ int aes_write_regv(struct fp_img_dev *dev, struct aes_regwrite *regs,
 	return 0;
 }
 
+int aes_assemble_image(unsigned char *input, size_t width, size_t height,
+	unsigned char *output)
+{
+	size_t frame_size = width * height;
+	size_t row, column;
+
+	for (column = 0; column < width; column++) {
+		for (row = 0; row < height; row += 2) {
+			output[width * row + column] = (*input & 0x07) * 36;
+			output[width * (row + 1) + column] = ((*input & 0x70) >> 4) * 36;
+			input++;
+		}
+	}
+}
+
diff --git a/libfprint/aeslib.h b/libfprint/aeslib.h
index 19b6cc6..c02f507 100644
--- a/libfprint/aeslib.h
+++ b/libfprint/aeslib.h
@@ -30,5 +30,8 @@ struct aes_regwrite {
 int aes_write_regv(struct fp_img_dev *dev, struct aes_regwrite *regs,
 	unsigned int num);
 
+int aes_assemble_image(unsigned char *input, size_t width, size_t height,
+	unsigned char *output);
+
 #endif
 
diff --git a/libfprint/drivers/aes1610.c b/libfprint/drivers/aes1610.c
index 5bc4d80..eb71a4b 100644
--- a/libfprint/drivers/aes1610.c
+++ b/libfprint/drivers/aes1610.c
@@ -231,15 +231,8 @@ static unsigned int assemble(unsigned char *input, unsigned char *output,
 	if (reverse)
 		output += (num_strips - 1) * FRAME_SIZE;
 	for (frame = 0; frame < num_strips; frame++) {
-		int column;
-		for (column = 0; column < FRAME_WIDTH; column++) {
-			int row;
-			for (row = 0; row < (FRAME_HEIGHT / 2); row++) {
-				output[FRAME_WIDTH * ( 2 * row) + column] = *input & 0x0F;
-				output[FRAME_WIDTH * ( 2 * row + 1) + column] = *input >> 4;
-				input++;
-			}
-		}
+		aes_assemble_image(input, FRAME_WIDTH, FRAME_HEIGHT, output);
+		input += FRAME_WIDTH * (FRAME_HEIGHT / 2);
 
 		if (reverse)
 			output -= FRAME_SIZE;
@@ -410,6 +403,7 @@ static int capture(struct fp_img_dev *dev, gboolean unconditional,
 	unsigned char *cooked;
 	unsigned char *imgptr;
 	unsigned char buf[665];
+	int final_size;
 	int sum;
 	unsigned int count_blank = 0;
 	int i;
@@ -511,10 +505,9 @@ static int capture(struct fp_img_dev *dev, gboolean unconditional,
 		fp_dbg("reversed scan direction");
 	}
 
-	for (i = 0; i < img->height * FRAME_WIDTH; i++)
-		img->data[i] = (cooked[i] << 4) | 0xf;
-
-	img = fpi_img_resize(img, img->height * FRAME_WIDTH);
+	final_size = img->height * FRAME_WIDTH;
+	memcpy(img->data, cooked, final_size);
+	img = fpi_img_resize(img, final_size);
 	*ret = img;
 	return 0;
 err:
diff --git a/libfprint/drivers/aes2501.c b/libfprint/drivers/aes2501.c
index 2abfa4e..ff7cd10 100644
--- a/libfprint/drivers/aes2501.c
+++ b/libfprint/drivers/aes2501.c
@@ -394,15 +394,8 @@ static unsigned int assemble(unsigned char *input, unsigned char *output,
 	if (reverse)
 		output += (num_strips - 1) * FRAME_SIZE;
 	for (frame = 0; frame < num_strips; frame++) {
-		int column;
-	    for (column = 0; column < FRAME_WIDTH; column++) {
-			int row;
-			for (row = 0; row < (FRAME_HEIGHT / 2); row++) {
-				output[FRAME_WIDTH * ( 2 * row) + column] = *input & 0x0F;
-				output[FRAME_WIDTH * ( 2 * row + 1) + column] = *input >> 4;
-				input++;
-			}
-		}
+		aes_assemble_image(input, FRAME_WIDTH, FRAME_HEIGHT, output);
+		input += FRAME_WIDTH * (FRAME_HEIGHT / 2);
 
 		if (reverse)
 		    output -= FRAME_SIZE;
@@ -492,8 +485,8 @@ static int capture(struct fp_img_dev *dev, gboolean unconditional,
 	unsigned char *cooked;
 	unsigned char *imgptr;
 	unsigned char buf[1705];
+	int final_size;
 	int sum;
-	int i;
 
 	/* FIXME can do better here in terms of buffer management? */
 	fp_dbg("");
@@ -563,10 +556,9 @@ static int capture(struct fp_img_dev *dev, gboolean unconditional,
 		fp_dbg("reversed scan direction");
 	}
 
-	for (i = 0; i < img->height * FRAME_WIDTH; i++)
-		img->data[i] = (cooked[i] << 4) | 0xf;
-
-	img = fpi_img_resize(img, img->height * FRAME_WIDTH);
+	final_size = img->height * FRAME_WIDTH;
+	memcpy(img->data, cooked, final_size);
+	img = fpi_img_resize(img, final_size);
 	*ret = img;
 	return 0;
 err:
diff --git a/libfprint/drivers/aes4000.c b/libfprint/drivers/aes4000.c
index f300477..f2c737f 100644
--- a/libfprint/drivers/aes4000.c
+++ b/libfprint/drivers/aes4000.c
@@ -34,20 +34,6 @@
 #define NR_SUBARRAYS	6
 #define SUBARRAY_LEN	768
 
-static void process_subarray(unsigned char *src, unsigned char *dst)
-{
-	int col, row;
-	int offset = -1;
-
-	for (col = 95; col >= 0; col--) {
-		for (row = 15; row >= 0; row -= 2) {
-			unsigned char val = src[++offset];
-			dst[(row * 96) + col] = (val & 0x7) * 36;
-			dst[((row - 1) * 96) + col] = ((val & 0x70) >> 4) * 36;
-		}
-	}
-}
-
 static const struct aes_regwrite init_reqs[] = {
 	/* master reset */
 	{ 0x80, 0x01 },
@@ -156,14 +142,14 @@ retry:
 		goto err;
 	}
 
-	for (i = NR_SUBARRAYS - 1; i >= 0; i--) {
+	for (i = 0; i < NR_SUBARRAYS; i++) {
 		fp_dbg("subarray header byte %02x", *ptr);
 		ptr++;
-		process_subarray(ptr, img->data + (i * 96 * 16));
+		aes_assemble_image(ptr, 96, 16, img->data + (i * 96 * 16));
 		ptr += SUBARRAY_LEN;
 	}
 
-	img->flags = FP_IMG_COLORS_INVERTED;
+	img->flags = FP_IMG_COLORS_INVERTED | FP_IMG_V_FLIPPED | FP_IMG_H_FLIPPED;
 	*ret = img;
 	g_free(data);
 	return 0;