diff --git a/ports/WCH/ch32v30x/board_flash.c b/ports/WCH/ch32v30x/board_flash.c
index 8f0a833..b0dc87a 100644
--- a/ports/WCH/ch32v30x/board_flash.c
+++ b/ports/WCH/ch32v30x/board_flash.c
@@ -100,9 +100,15 @@ __attribute__((weak)) void board_flash_flush(void) {}
 
 __attribute__((weak)) void board_flash_write(uint32_t addr, void const *data, uint32_t len) {
     uint32_t flash_addr = FLASH_BASE_ADDR + addr;
-    FLASH_Unlock();
-    flash_write(flash_addr, data, len);
-    FLASH_Lock();
+    if (len == 256) {
+        FLASH_Unlock_Fast();
+        FLASH_ProgramPage_Fast(flash_addr, data);
+        FLASH_Lock_Fast();
+    } else {
+        FLASH_Unlock();
+        flash_write(flash_addr, data, len);
+        FLASH_Lock();
+    }
 }
 
 __attribute__((weak)) void board_flash_erase_app(void) {}
diff --git a/ports/WCH/ch32v30x/boards/ch32v305rbt6/board.h b/ports/WCH/ch32v30x/boards/ch32v305rbt6/board.h
new file mode 100644
index 0000000..2dd7e56
--- /dev/null
+++ b/ports/WCH/ch32v30x/boards/ch32v305rbt6/board.h
@@ -0,0 +1,66 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Zhaqian
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef BOARD_H_
+#define BOARD_H_
+
+#include "ch32v30x.h"
+
+// clang-format off
+//--------------------------------------------------------------------+
+// LED
+//--------------------------------------------------------------------+
+#define LED_PORT             GPIOA
+#define LED_PIN              GPIO_Pin_3
+#define LED_STATE_ON         0
+
+//--------------------------------------------------------------------+
+// FLASH
+//--------------------------------------------------------------------+
+#define BOARD_SECTOR_SIZE   4096U
+#define BOARD_SECTOR_COUNT  36
+#define BOARD_FLASH_SIZE    (BOARD_SECTOR_SIZE * BOARD_SECTOR_COUNT)
+
+//--------------------------------------------------------------------+
+// USB UF2
+//--------------------------------------------------------------------+
+#define USBD_VID            0x00AA
+#define USBD_PID            0xAAFF
+#define USB_MANUFACTURER    "WCH"
+#define USB_PRODUCT         "CH32V305"
+
+#define UF2_PRODUCT_NAME    USB_MANUFACTURER " " USB_PRODUCT
+#define UF2_BOARD_ID        "CH32V305xB"
+#define UF2_VOLUME_LABEL    "CherryUF2"
+#define UF2_INDEX_URL       "https://www.wch.cn/products/CH32V305.html"
+
+// clang-format on
+//--------------------------------------------------------------------+
+// CLOCK
+//--------------------------------------------------------------------+
+static inline void clock_init(void) {
+    // TODO
+}
+
+#endif
diff --git a/ports/WCH/ch32v30x/boards/ch32v305rbt6/board.mk b/ports/WCH/ch32v30x/boards/ch32v305rbt6/board.mk
new file mode 100644
index 0000000..f82aedd
--- /dev/null
+++ b/ports/WCH/ch32v30x/boards/ch32v305rbt6/board.mk
@@ -0,0 +1,9 @@
+CFLAGS += \
+  -DCH32V30x_D8C \
+  -DHSE_VALUE=8000000U \
+  -DCONFIG_USB_HS
+
+SRC_S += \
+  $(WCH_CMSIS)/Startup/startup_ch32v30x_D8C.S
+
+USB_XFER_SPEED = HS
\ No newline at end of file