root化後に下記の手順を実行
Native SMS Nexus 7 3G texting send/receive/manage with stock JB mms.apk
Download file
Unzip
Load "mms.apk" into system/app and set permissions
Reboot
./abd shell ... login to Android device
./abd push xxxx.apk /system/app ... apkをインストール
Error "Read-only file system" ==>
mount -rw -o remount /dev/block/mtdblock1 /system
