首先拿到供应商提供的so库，将so放到vendor\rockchip\common\phone\lib下

修改对应的phone.mk，将so库移动指定位置（Android7以下移动到system/lib,android8以后移动到vendor/lib）

CUR_PATH := vendor/rockchip/common

#########################################################
#   3G Dongle SUPPORT
#########################################################
PRODUCT_COPY_FILES += \
    $(CUR_PATH)/phone/etc/ppp/ip-down:system/etc/ppp/ip-down \
    $(CUR_PATH)/phone/etc/ppp/ip-up:system/etc/ppp/ip-up \
    $(CUR_PATH)/phone/etc/ppp/ip-up:system/etc/ppp/ip-up-vpn \
    $(CUR_PATH)/phone/etc/ppp/call-pppd:system/etc/ppp/call-pppd \
    $(CUR_PATH)/phone/etc/operator_table:system/etc/operator_table \
    $(CUR_PATH)/phone/lib/libreference-ril-n58.so:system/lib/libreference-ril-n58.so \
    $(CUR_PATH)/phone/lib/libreference-ril.so:vendor/lib/libreference-ril.so 

修改device/rockchip/common/BoardConfig.mk

#enable 3g dongle
BOARD_HAVE_DONGLE ?= true

修改device/rockchip/common/init.connectivity.rc，添加ppp,不然会没有网络使用

chmod 0777 /dev/ppp

修改device/rockchip/rk3288/init.rk3288.rc

service ril-daemon /vendor/bin/hw/rild -l /vendor/lib/libreference-ril.so
    class main
    user root
    group radio cache inet misc audio sdcard_rw log
    capabilities BLOCK_SUSPEND NET_ADMIN NET_RAW

修改device/rockchip/rk3288/manifest.xml

    <hal format="hidl">
        <name>android.hardware.radio</name>
        <transport>hwbinder</transport>
        <version>1.0</version>
        <interface>
            <name>IRadio</name>
            <instance>slot1</instance>
        </interface>
        <interface>
            <name>ISap</name>
            <instance>slot1</instance>
        </interface>
    </hal>
    <hal format="hidl">
        <name>android.hardware.radio.deprecated</name>
        <transport>hwbinder</transport>
        <version>1.0</version>
        <interface>
            <name>IOemHook</name>
            <instance>slot1</instance>
        </interface>
    </hal>

修改device/rockchip/common/ueventd.rockchip.rc

# for radio
/dev/ttyUSB0              0660   radio		radio
/dev/ttyUSB1              0660   radio		radio
/dev/ttyUSB2              0660   radio		radio
/dev/ttyUSB3              0660   radio		radio
/dev/ttyUSB4              0660   radio		radio
/dev/ttyUSB5              0660   radio		radio
/dev/ttyUSB6              0660   radio		radio
/dev/ttyUSB7              0660   radio		radio
/dev/ttyUSB8              0660   radio		radio
/dev/ttyUSB9              0660   radio		radio

/dev/ttyUSB*              0660   radio      radio
/dev/ttyACM*              0660   radio      radio
/dev/cdc-wdm*		      0660	 radio		radio
/dev/qcqmi*		          0660	 radio		radio
/dev/cdc-acm*		      0660	 radio		radio

#PCIe
/dev/mhi_DUN 0660 radio radio
/dev/mhi_DIAG 0660 radio radio
/dev/mhi_BHI 0660 radio radio
/dev/mhi_LOOPBACK 0660 radio radio
/dev/mhi_QMI0 0660 radio radio

修改device/rockchip/common/sepolicy/file_contexts

/dev/ttyFIQ[0-9]*    u:object_r:serial_device:s0
/dev/ttyUSB[0-9]*    u:object_r:radio_device:s0
/dev/ttyCOM[0-9]*    u:object_r:tty_device:s0
/dev/ttyACM[0-9]*    u:object_r:tty_device:s0
/dev/cdc-wdm[0-9]*    u:object_r:radio_device:s0
/dev/qcqmi[0-9]*    u:object_r:radio_device:s0
/vendor/bin/hw/rild u:object_r:rild_exec:s0
/dev/socket/rildOemHook    u:object_r:rild_exec:s0

#PCIe
/dev/mhi_DUN u:object_r:radio_device:s0
/dev/mhi_DIAG u:object_r:radio_device:s0
/dev/mhi_BHI u:object_r:radio_device:s0
/dev/mhi_LOOPBACK u:object_r:radio_device:s0
/dev/mhi_QMI0 u:object_r:radio_device:s0

修改device/rockchip/common/sepolicy/rild.te

allow rild self:packet_socket { create bind write read };

通过adb logcat -b radio -v time抓取radio日志

修改device/rockchip/rk3288/overlay/frameworks/base/core/res/res/values/config.xml

修改mobile

    <string-array translatable="false" name="networkAttributes">
        <item>"wifi,1,1,2,-1,true"</item>
        <item>"mobile,0,0,0,-1,true"</item>
        <item>"mobile_mms,2,0,4,60000,true"</item>
        <item>"mobile_supl,3,0,2,60000,true"</item>
        <item>"mobile_dun,4,0,2,60000,true"</item>
        <item>"mobile_hipri,5,0,3,60000,true"</item>
        <item>"mobile_fota,10,0,2,60000,true"</item>
        <item>"mobile_ims,11,0,2,60000,true"</item>
        <item>"mobile_cbs,12,0,2,60000,true"</item>

        <item>"bluetooth,7,7,0,-1,true"</item>
        <item>"ethernet,9,9,9,-1,true"</item>
<!--add by blb-->
        <item>"pppoe,15,15,5,-1,true"</item>
    </string-array>

修改device/rockchip/common/overlay/frameworks/base/core/res/res/values/config.xml

    <bool name="config_voice_capable">true</bool>

    <!-- This device does not allow sms service. -->
    <bool name="config_sms_capable">true</bool>

device/rockchip/common/init.rk30board.rc

# for telephony function
on property:ro.boot.noril=false
    setprop ro.radio.noril false
    start ril-daemon

修改defconfig

CONFIG_USB_SERIAL=y
CONFIG_USB_SERIAL_GENERIC=y
CONFIG_USB_SERIAL_WWAN=y
CONFIG_USBNET=y
CONFIG_USB_SERIAL_OPTION=y