diff --git a/f3probe.c b/f3probe.c
index 61420c4..d6204ce 100644
--- a/f3probe.c
+++ b/f3probe.c
@@ -43,6 +43,8 @@ static struct argp_option options[] = {
 		"Run a unit test; it ignores all other debug options",	0},
 	{"destructive",		'n',	NULL,		0,
 		"Do not restore blocks of the device after probing it",	2},
+	{"manual-reset",	'm',	NULL,		0,
+		"Ask user to manually reset the drive",	0},
 	{ 0 }
 };
 
@@ -59,6 +61,9 @@ struct args {
 	uint64_t	fake_size_byte;
 	int		wrap;
 	int		block_order;
+
+	bool		manual_reset;
+	/* 3 free bytes. */
 };
 
 static long long arg_to_long_long(const struct argp_state *state,
@@ -132,6 +137,10 @@ static error_t parse_opt(int key, char *arg, struct argp_state *state)
 		args->save = false;
 		break;
 
+	case 'm':
+		args->manual_reset = true;
+		break;
+
 	case ARGP_KEY_INIT:
 		args->filename = NULL;
 		break;
@@ -284,7 +293,7 @@ static int test_device(struct args *args)
 		? create_file_device(args->filename, args->real_size_byte,
 			args->fake_size_byte, args->wrap, args->block_order,
 			args->keep_file)
-		: create_block_device(args->filename);
+		: create_block_device(args->filename, args->manual_reset);
 	assert(dev);
 
 	if (args->save) {
@@ -345,6 +354,7 @@ int main(int argc, char **argv)
 		.fake_size_byte	= 1ULL << 34,
 		.wrap		= 31,
 		.block_order	= 9,
+		.manual_reset	= false,
 	};
 
 	/* Read parameters. */
diff --git a/libprobe.c b/libprobe.c
index 075df7c..db5a777 100644
--- a/libprobe.c
+++ b/libprobe.c
@@ -324,6 +324,21 @@ static inline int bdev_open(const char *filename)
 	return open(filename, O_RDWR | O_DIRECT | O_SYNC);
 }
 
+/* XXX Monitor the USB subsytem to know when the drive was unplugged and
+ * plugged back to continue instead of waiting for a key.
+ */
+static int bdev_manual_reset(struct device *dev)
+{
+	struct block_device *bdev = dev_bdev(dev);
+	assert(!close(bdev->fd));
+	printf("Please unplug and plug back the USB drive, and press a key to continue...\n");
+	getchar();
+	bdev->fd = bdev_open(bdev->filename);
+	if (bdev->fd < 0)
+		err(errno, "Can't REopen device `%s'", bdev->filename);
+	return 0;
+}
+
 static int bdev_reset(struct device *dev)
 {
 	struct block_device *bdev = dev_bdev(dev);
@@ -338,8 +353,10 @@ static int bdev_reset(struct device *dev)
 static void bdev_free(struct device *dev)
 {
 	struct block_device *bdev = dev_bdev(dev);
-	assert(!close(bdev->hw_fd));
-	assert(!close(bdev->fd));
+	if (bdev->hw_fd >= 0)
+		assert(!close(bdev->hw_fd));
+	if (bdev->fd >= 0)
+		assert(!close(bdev->fd));
 	free((void *)bdev->filename);
 }
 
@@ -446,14 +463,14 @@ static int ilog2(uint64_t x)
  * Suggest how to call f3probe with the correct device name if
  * the block device is a partition.
  * Use udev to do these tests.
+ * Make sure that no partition of the drive is mounted.
  */
 /* XXX Test for write access of the block device to give
  * a nice error message.
  * If it fails, suggest running f3probe as root.
  */
-struct device *create_block_device(const char *filename)
+struct device *create_block_device(const char *filename, int manual_reset)
 {
-	const char *usb_filename;
 	struct block_device *bdev;
 	int block_size;
 
@@ -476,18 +493,25 @@ struct device *create_block_device(const char *filename)
 		goto fd;
 	}
 
-	/* XXX Add support for block devices backed by SCSI, SATA, and ATA. */
-	usb_filename = map_block_to_usb_dev(filename);
-	if (!usb_filename) {
-		err(EINVAL, "Block device `%s' is not backed by a USB device",
-			filename);
-		goto fd;
-	}
+	if (manual_reset) {
+		bdev->hw_fd = -1;
+		bdev->dev.reset	= bdev_manual_reset;
+	} else {
+		/* XXX Add support for block devices backed by SCSI and ATA. */
+		const char *usb_filename = map_block_to_usb_dev(filename);
+		if (!usb_filename) {
+			err(EINVAL, "Block device `%s' is not backed by a USB device",
+				filename);
+			goto fd;
+		}
 
-	bdev->hw_fd = open(usb_filename, O_WRONLY | O_NONBLOCK);
-	if (bdev->hw_fd < 0) {
-		err(errno, "Can't open device `%s'", usb_filename);
-		goto usb_filename;
+		bdev->hw_fd = open(usb_filename, O_WRONLY | O_NONBLOCK);
+		free((void *)usb_filename);
+		if (bdev->hw_fd < 0) {
+			err(errno, "Can't open device `%s'", usb_filename);
+			goto fd;
+		}
+		bdev->dev.reset = bdev_reset;
 	}
 
 	assert(!ioctl(bdev->fd, BLKGETSIZE64, &bdev->dev.size_byte));
@@ -498,14 +522,10 @@ struct device *create_block_device(const char *filename)
 
 	bdev->dev.read_block = bdev_read_block;
 	bdev->dev.write_block = bdev_write_block;
-	bdev->dev.reset	= bdev_reset;
 	bdev->dev.free = bdev_free;
 
-	free((void *)usb_filename);
 	return &bdev->dev;
 
-usb_filename:
-	free((void *)usb_filename);
 fd:
 	assert(!close(bdev->fd));
 filename:
diff --git a/libprobe.h b/libprobe.h
index eed1732..074f450 100644
--- a/libprobe.h
+++ b/libprobe.h
@@ -36,7 +36,7 @@ struct device *create_file_device(const char *filename,
 	uint64_t real_size_byte, uint64_t fake_size_byte, int wrap,
 	int block_order, int keep_file);
 
-struct device *create_block_device(const char *filename);
+struct device *create_block_device(const char *filename, int manual_reset);
 
 struct device *create_safe_device(struct device *dev, int max_blocks);