安装驱动（建议全装）
opkg install kmod-usb-core kmod-usb-ohci kmod-usb-serial kmod-usb-serial-ftdi kmod-usb-acm kmod-usb-atm
opkg install kmod-usb-acm kmod-usb-atm
可能就装这两个驱动就行
注释掉源
vi /etc/opkg/customfeeds.conf
vi /etc/opkg/distfeeds.conf
src/gz openwrt_core http://mirrors.ustc.edu.cn/openwrt/releases/19.07.3/targets/x86/64/pa
src/gz openwrt_base http://mirrors.ustc.edu.cn/openwrt/releases/19.07.3/packages/x86_64/b
src/gz openwrt_luci http://mirrors.ustc.edu.cn/openwrt/releases/19.07.3/packages/x86_64/l
src/gz openwrt_packages http://mirrors.ustc.edu.cn/openwrt/releases/19.07.3/packages/x86_
src/gz openwrt_routing http://mirrors.ustc.edu.cn/openwrt/releases/19.07.3/packages/x86_6
src/gz openwrt_telephony http://mirrors.ustc.edu.cn/openwrt/releases/19.07.3/packages/x86
src/gz mmdvm http://downloads.ostar.me/releases/19.07/packages/x86_64/mmdvm
src/gz ostar_mmdvm http://downloads.ostar.me/releases/19.07/packages/
只留
opkg update
opkg install mmdvm
mmdvmctl update
输入2次，连续升级
