diff --git a/cdba-server.c b/cdba-server.c
index cc538ca..2b16661 100644
--- a/cdba-server.c
+++ b/cdba-server.c
@@ -55,12 +55,14 @@ static struct fastboot_ops fastboot_ops = {
 
 static void msg_select_board(const void *param)
 {
-	selected_device = device_open(param, username, &fastboot_ops);
+	selected_device = device_open(param, username);
 	if (!selected_device) {
 		fprintf(stderr, "failed to open %s\n", (const char *)param);
 		watch_quit();
 	}
 
+	device_fastboot_open(selected_device, &fastboot_ops);
+
 	cdba_send(MSG_SELECT_BOARD);
 }
 
diff --git a/device.c b/device.c
index 5baaf76..79ce6a5 100644
--- a/device.c
+++ b/device.c
@@ -95,8 +95,7 @@ static bool device_check_access(struct device *device,
 }
 
 struct device *device_open(const char *board,
-			   const char *username,
-			   struct fastboot_ops *fastboot_ops)
+			   const char *username)
 {
 	struct device *device;
 
@@ -136,8 +135,6 @@ found:
 	if (device->usb_always_on)
 		device_usb(device, true);
 
-	device->fastboot = fastboot_open(device->serial, fastboot_ops, NULL);
-
 	return device;
 }
 
@@ -275,18 +272,36 @@ int device_write(struct device *device, const void *buf, size_t len)
 	return device_console(device, write, buf, len);
 }
 
+void device_fastboot_open(struct device *device,
+			  struct fastboot_ops *fastboot_ops)
+{
+	device->fastboot = fastboot_open(device->serial, fastboot_ops, NULL);
+}
+
 void device_fastboot_boot(struct device *device)
 {
+	if (!device->fastboot) {
+		fprintf(stderr, "fastboot not opened\n");
+		return;
+	}
 	fastboot_boot(device->fastboot);
 }
 
 void device_fastboot_continue(struct device *device)
 {
+	if (!device->fastboot) {
+		fprintf(stderr, "fastboot not opened\n");
+		return;
+	}
 	fastboot_continue(device->fastboot);
 }
 
 void device_fastboot_flash_reboot(struct device *device)
 {
+	if (!device->fastboot) {
+		fprintf(stderr, "fastboot not opened\n");
+		return;
+	}
 	fastboot_flash(device->fastboot, "boot");
 	fastboot_reboot(device->fastboot);
 }
diff --git a/device.h b/device.h
index 6d431bc..220eeb0 100644
--- a/device.h
+++ b/device.h
@@ -72,8 +72,7 @@ struct device_user {
 void device_add(struct device *device);
 
 struct device *device_open(const char *board,
-			   const char *username,
-			   struct fastboot_ops *fastboot_ops);
+			   const char *username);
 void device_close(struct device *dev);
 int device_power(struct device *device, bool on);
 
@@ -83,6 +82,8 @@ int device_write(struct device *device, const void *buf, size_t len);
 
 void device_boot(struct device *device, const void *data, size_t len);
 
+void device_fastboot_open(struct device *device,
+			  struct fastboot_ops *fastboot_ops);
 void device_fastboot_boot(struct device *device);
 void device_fastboot_flash_reboot(struct device *device);
 void device_send_break(struct device *device);