在 Nexus S（2.3 原版）上：
$ adb shell cat /system/build.prop | grep rild
rild.libpath=/vendor/lib/libsec-ril.so
rild.libargs=-d /dev/ttyS0
在 Nexus 4（4.4 vanilla）上：
$ adb shell cat /system/build.prop | grep rild
$
这个道具出现在我所有的 Android 手机上：三星 Galaxy Trend (4.1)、阿尔卡特 One Touch Pixie (2.3)、摩托罗拉 Moto G (4.3)，但在 Nexus 4 上没有。
完整的 build.prop：
# begin build properties
# autogenerated by buildinfo.sh
ro.build.id=KOT49H
ro.build.display.id=KOT49H
ro.build.version.incremental=937116
ro.build.version.sdk=19
ro.build.version.codename=REL
ro.build.version.release=4.4.2
ro.build.date=Wed Dec 4 23:40:01 UTC 2013
ro.build.date.utc=1386200401
ro.build.type=user
ro.build.user=android-build
ro.build.host=kpfj3.cbf.corp.google.com
ro.build.tags=release-keys
ro.product.model=Nexus 4
ro.product.brand=google
ro.product.name=occam
ro.product.device=mako
ro.product.board=MAKO
ro.product.cpu.abi=armeabi-v7a
ro.product.cpu.abi2=armeabi
ro.product.manufacturer=LGE
ro.product.locale.language=en
ro.product.locale.region=US
ro.wifi.channels=
ro.board.platform=msm8960
# ro.build.product is obsolete; use ro.product.device
ro.build.product=mako
# Do not try to parse ro.build.description or .fingerprint
ro.build.description=occam-user 4.4.2 KOT49H 937116 release-keys
ro.build.fingerprint=google/occam/mako:4.4.2/KOT49H/937116:user/release-keys
ro.build.characteristics=nosdcard
# end build properties
#
# ADDITIONAL_BUILD_PROPERTIES
#
ro.config.ringtone=Themos.ogg
ro.config.notification_sound=Tejat.ogg
ro.config.alarm_alert=Oxygen.ogg
ro.com.android.dateformat=MM-dd-yyyy
ro.com.android.dataroaming=false
ro.url.legal=http://www.google.com/intl/%s/mobile/android/basic/phone-legal.html
ro.url.legal.android_privacy=http://www.google.com/intl/%s/mobile/android/basic/privacy.html
ro.com.google.clientidbase=android-google
ro.carrier=unknown
ro.com.android.wifi-watchlist=GoogleGuest
ro.error.receiver.system.apps=com.google.android.gms
ro.setupwizard.enterprise_mode=1
ro.opengles.version=196608
ro.sf.lcd_density=320
persist.audio.handset.mic.type=digital
persist.audio.dualmic.config=endfire
persist.audio.fluence.voicecall=true
persist.audio.handset.mic=dmic
persist.audio.fluence.mode=endfire
persist.audio.lowlatency.rec=false
af.resampler.quality=4
persist.radio.apm_sim_not_pwdn=1
ro.telephony.call_ring.multiple=0
persist.hwc.mdpcomp.enable=true
ro.qualcomm.bt.hci_transport=smd
telephony.lteOnCdmaDevice=0
drm.service.enabled=true
wifi.interface=wlan0
wifi.supplicant_scan_interval=15
media.aac_51_output_enabled=true
debug.egl.recordable.rgba8888=1
ro.qc.sensors.wl_dis=true
ro.qualcomm.sensors.smd=true
dalvik.vm.heapstartsize=8m
dalvik.vm.heapgrowthlimit=192m
dalvik.vm.heapsize=512m
dalvik.vm.heaptargetutilization=0.75
dalvik.vm.heapminfree=512k
dalvik.vm.heapmaxfree=8m
keyguard.no_require_sim=true
ro.facelock.black_timeout=400
ro.facelock.det_timeout=1500
ro.facelock.rec_timeout=2500
ro.facelock.lively_timeout=2500
ro.facelock.est_max_time=600
ro.facelock.use_intro_anim=false
persist.sys.dalvik.vm.lib=libdvm.so
dalvik.vm.dexopt-flags=m=y
net.bt.name=Android
dalvik.vm.stack-trace-file=/data/anr/traces.txt
第一个问题：Nexus 4 的这个“功能”还是整个 Android 4.4？第二个问题：这种情况下应该如何确定无线接口位置？