【提问】：HF-A21 boot fault, need help
【详情】：After downloading the firmware to the hf-a21-0 module via the web interface, the module stopped working. Now it reboots every 4-5 seconds. Is there a way to reset it in this state to the factory firmware, or load a new firmware into it? Do you have detailed information on working with the built-in bootloader? 通过Web界面将固件下载到hf-a21-0模块后，该模块停止工作。 现在，它每4-5秒重新启动一次。 有没有办法在这种状态下将其重置为出厂固件，或将新固件加载到其中？ 您是否有使

【回答】：可以联系我们模块技术支持郑工支持下，联系电话16621188242