diff --git a/libfprint/drivers/aes1610.c b/libfprint/drivers/aes1610.c
index 5a29080..7e4d945 100644
--- a/libfprint/drivers/aes1610.c
+++ b/libfprint/drivers/aes1610.c
@@ -612,7 +612,7 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer)
 		aes_write_regv(dev, capture_stop, G_N_ELEMENTS(capture_stop), stub_capture_stop_cb, NULL);
 		aesdev->strips = g_slist_reverse(aesdev->strips);
 		fpi_do_movement_estimation(&assembling_ctx, aesdev->strips);
-		img = fpi_assemble_frames(&assembling_ctx, aesdev->strips, aesdev->strips_len);
+		img = fpi_assemble_frames(&assembling_ctx, aesdev->strips);
 		img->flags |= FP_IMG_PARTIAL;
 		g_slist_free_full(aesdev->strips, g_free);
 		aesdev->strips = NULL;
diff --git a/libfprint/drivers/aes2501.c b/libfprint/drivers/aes2501.c
index ef705e7..9df2bcd 100644
--- a/libfprint/drivers/aes2501.c
+++ b/libfprint/drivers/aes2501.c
@@ -483,8 +483,7 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer,
 
 			aesdev->strips = g_slist_reverse(aesdev->strips);
 			fpi_do_movement_estimation(&assembling_ctx, aesdev->strips);
-			img = fpi_assemble_frames(&assembling_ctx,
-						  aesdev->strips, aesdev->strips_len);
+			img = fpi_assemble_frames(&assembling_ctx, aesdev->strips);
 			img->flags |= FP_IMG_PARTIAL;
 			g_slist_free_full(aesdev->strips, g_free);
 			aesdev->strips = NULL;
diff --git a/libfprint/drivers/aes2550.c b/libfprint/drivers/aes2550.c
index 72a8613..b17f295 100644
--- a/libfprint/drivers/aes2550.c
+++ b/libfprint/drivers/aes2550.c
@@ -244,8 +244,7 @@ static void capture_set_idle_reqs_cb(struct libusb_transfer *transfer)
 		struct fp_img *img;
 
 		aesdev->strips = g_slist_reverse(aesdev->strips);
-		img = fpi_assemble_frames(&assembling_ctx,
-					  aesdev->strips, aesdev->strips_len);
+		img = fpi_assemble_frames(&assembling_ctx, aesdev->strips);
 		img->flags |= FP_IMG_PARTIAL;
 		g_slist_free_full(aesdev->strips, g_free);
 		aesdev->strips = NULL;
diff --git a/libfprint/drivers/aesx660.c b/libfprint/drivers/aesx660.c
index 47da51f..2990d3d 100644
--- a/libfprint/drivers/aesx660.c
+++ b/libfprint/drivers/aesx660.c
@@ -305,7 +305,7 @@ static void capture_set_idle_cmd_cb(struct libusb_transfer *transfer)
 		struct fp_img *img;
 
 		aesdev->strips = g_slist_reverse(aesdev->strips);
-		img = fpi_assemble_frames(aesdev->assembling_ctx, aesdev->strips, aesdev->strips_len);
+		img = fpi_assemble_frames(aesdev->assembling_ctx, aesdev->strips);
 		img->flags |= aesdev->extra_img_flags;
 		g_slist_foreach(aesdev->strips, (GFunc) g_free, NULL);
 		g_slist_free(aesdev->strips);
diff --git a/libfprint/drivers/elan.c b/libfprint/drivers/elan.c
index 8bc7e50..65209fb 100644
--- a/libfprint/drivers/elan.c
+++ b/libfprint/drivers/elan.c
@@ -308,7 +308,7 @@ static void elan_submit_image(struct fp_img_dev *dev)
 	assembling_ctx.image_width = elandev->frame_width * 3 / 2;
 	g_slist_foreach(raw_frames, (GFunc) elandev->process_frame, &frames);
 	fpi_do_movement_estimation(&assembling_ctx, frames);
-	img = fpi_assemble_frames(&assembling_ctx, frames, num_frames);
+	img = fpi_assemble_frames(&assembling_ctx, frames);
 
 	img->flags |= FP_IMG_PARTIAL;
 	fpi_imgdev_image_captured(dev, img);
diff --git a/libfprint/fpi-assembling.c b/libfprint/fpi-assembling.c
index cb911a8..1bc3bef 100644
--- a/libfprint/fpi-assembling.c
+++ b/libfprint/fpi-assembling.c
@@ -248,45 +248,34 @@ static inline void aes_blit_stripe(struct fpi_frame_asmbl_ctx *ctx,
  * fpi_assemble_frames:
  * @ctx: #fpi_frame_asmbl_ctx - frame assembling context
  * @stripes: linked list of #fpi_frame
- * @num_stripes: number of items in @stripes to process
  *
  * fpi_assemble_frames() assembles individual frames into a single image.
  * It expects @delta_x and @delta_y of #fpi_frame to be populated.
  *
- * Note that @num_stripes might be shorter than the length of the list,
- * if some stripes should be skipped.
- *
  * Returns: a newly allocated #fp_img.
  */
 struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes)
+				   GSList                     *stripes)
 {
-	GSList *stripe;
+	GSList *l;
 	struct fp_img *img;
 	int height = 0;
-	int i, y, x;
+	int y, x;
 	gboolean reverse = FALSE;
 	struct fpi_frame *fpi_frame;
 
 	//FIXME g_return_if_fail
-	BUG_ON(num_stripes == 0);
 	BUG_ON(ctx->image_width < ctx->frame_width);
 
-	/* Calculate height */
-	i = 0;
-	stripe = stripes;
-
 	/* No offset for 1st image */
-	fpi_frame = stripe->data;
+	fpi_frame = stripes->data;
 	fpi_frame->delta_x = 0;
 	fpi_frame->delta_y = 0;
-	do {
-		fpi_frame = stripe->data;
+	for (l = stripes; l != NULL; l = l->next) {
+		fpi_frame = l->data;
 
 		height += fpi_frame->delta_y;
-		i++;
-		stripe = g_slist_next(stripe);
-	} while (i < num_stripes);
+	}
 
 	fp_dbg("height is %d", height);
 
@@ -306,13 +295,11 @@ struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
 	img->height = height;
 
 	/* Assemble stripes */
-	i = 0;
-	stripe = stripes;
 	y = reverse ? (height - ctx->frame_height) : 0;
 	x = (ctx->image_width - ctx->frame_width) / 2;
 
-	do {
-		fpi_frame = stripe->data;
+	for (l = stripes; l != NULL; l = l->next) {
+		fpi_frame = l->data;
 
 		if(reverse) {
 			y += fpi_frame->delta_y;
@@ -325,10 +312,7 @@ struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
 			y += fpi_frame->delta_y;
 			x += fpi_frame->delta_x;
 		}
-
-		stripe = g_slist_next(stripe);
-		i++;
-	} while (i < num_stripes);
+	}
 
 	return img;
 }
diff --git a/libfprint/fpi-assembling.h b/libfprint/fpi-assembling.h
index 1425e7a..5f86815 100644
--- a/libfprint/fpi-assembling.h
+++ b/libfprint/fpi-assembling.h
@@ -66,7 +66,7 @@ void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
 				GSList                     *stripes);
 
 struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes);
+				   GSList                     *stripes);
 
 /**
  * fpi_line_asmbl_ctx: