Non ho ben capito la parte del bulid.prop,io ho messo tutto in ordine come è nel post (tutto sotto,cioè dall'ultima stringa ho iniziato prima col 1° tweaks poi col 2° etc..)ma poi non si avviava il sistema,ho dovuto reinstallare.
Ecco il bulid.prop che avevo modificato :
# begin build properties
# autogenerated by buildinfo.sh
ro.build.id=JZO54K
ro.build.display.id=JZO54K.I8160XXMB4
ro.build.version.incremental=I8160XXMB4
ro.build.version.sdk=16
ro.build.version.codename=REL
ro.build.version.release=4.1.2
ro.build.date=Tue Feb 19 18:58:10 KST 2013
ro.build.date.utc=1361267890
ro.build.type=user
ro.build.user=se.infra
ro.build.host=SEP-97
ro.build.tags=release-keys
ro.build.changelist=978827
ro.product.model=GT-I8160
ro.product.brand=samsung
ro.product.name=GT-I8160
ro.product.device=GT-I8160
ro.product.board=montblanc
ro.product.cpu.abi=armeabi-v7a
# Samsung Specific Properties
ro.build.PDA=I8160XXMB4
ro.product.cpu.abi2=armeabi
ro.product_ship=true
ro.product.manufacturer=samsung
ro.product.locale.language=en
ro.product.locale.region=GB
ro.wifi.channels=
ro.board.platform=montblanc
# ro.build.product is obsolete; use ro.product.device
ro.build.product=GT-I8160
# Do not try to parse ro.build.description or .fingerprint
ro.build.description=GT-I8160-user 4.1.2 JZO54K I8160XXMB4 release-keys
ro.build.fingerprint=samsung/GT-I8160/GT-I8160:4.1.2/JZO54K/I8160XXMB4:user/release-keys
ro.build.characteristics=default
# end build properties
#
# system.prop for U8500
#
rild.libpath=/system/lib/libsec-ril.so
rild.libargs=-d /dev/ttyS0
# Graphics related configurations
ro.sf.lcd_density=240
ro.sf.display_rotation=0
# System property for Default Brightness
ro.lcd_brightness=150
ro.lcd_min_brightness=30
# The OpenGL ES API level that is natively supported by this device.
# This is a 16.16 fixed point number
ro.opengles.version=131072
# Enable RecoverySystem to emit "factory-reset" reset string
# instead of "recovery" when doing a factory reset. This is
# useful when implementing factory reset without the entire
# recovery framework.
ro.factoryresetwithoutrecovery=true
# debug.sf.hw=0 Use b2r2 as compositor in SurfaceFlinger
# debug.sf.hw=1 Use Mali as compositor in SurfaceFlinger
debug.sf.hw=1
# Android defaults EGL preserved swap behaviour
# This gives bad performace for deferred renderers
# such as Mali.
debug.hwui.render_dirty_regions=false
# STE: Low power audio - enable ULP mode
ste.nmf.autoidle=1
# STE: Address of DBus STE bus
ste.dbus.bus.address=unix
ath=/dev/socket/dbus_ste
# STE: UNSOL_CALL_RING is only sent once from RIL.
# Android needs to generate more rings if needed.
ro.telephony.call_ring.multiple=false
# STE: Hardware video codecs configuration
ste.video.dec.mpeg4.in.size=8192
ste.video.enc.out.buffercnt=5
ste.video.dec.recycle.delay=1
#STE: Fast Dormancy Flag
# Fast Dormancy based on USB Tether Events and Screen States
ste.special_fast_dormancy=false
# STE: camera orientation front & back
ste.cam.front.orientation=270
ste.cam.back.orientation=90
#UAP for streaming
net.streaming.rtsp.uaprof=http://wap.samsungmobile.com/uaprof/GT-I8160.xml
net.streaming.rtsp.uaprof.bo=http://wap.samsungmobile.com/uaprof/GT-I8160BO.xml
#
# system prop for issue regarding writable directories(SDT)
#
ro.kernel.qemu=0
#
# ADDITIONAL_BUILD_PROPERTIES
#
ro.carrier=unknown
dalvik.vm.heapstartsize=8m
dalvik.vm.heapgrowthlimit=64m
dalvik.vm.heapsize=256m
ro.sf.lcd_density=240
ro.sec.fle.encryption=true
ro.error.receiver.default=com.samsung.receiver.err or
persist.sys.usb.config=mtp
ro.config.ringtone=S_Over_the_horizon.ogg
ro.config.notification_sound=S_Whistle.ogg
ro.config.alarm_alert=Walk_in_the_forest.ogg
ro.config.media_sound=Media_preview_Touch_the_ligh t.ogg
ro.setupwizard.mode=DISABLED
ro.com.google.clientidbase=android-samsung
ro.com.google.gmsversion=4.1_r4
keyguard.no_require_sim=true
net.bt.name=Android
dalvik.vm.stack-trace-file=/data/anr/traces.txt
#Tweaks Increase download/upload/3G speeds
ro.ril.hsxpa=2
ro.ril.gprsclass=10
ro.ril.hep=1
ro.ril.enable.dtm=0
ro.ril.hsdpa.category=8 (or 10,12,14) Still looking for more of these though.
ro.ril.enable.a53=1
ro.ril.enable.3g.prefix=1
ro.ril.htcmaskw1.bitmask=4294967295
ro.ril.htcmaskw1=14449
ro.ril.hsupa.category=6
net.tcp.buffersize.default=4096,87380,256960,4096, 16384,256960
net.tcp.buffersize.wifi=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.umts=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.gprs=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.edge=4096,87380,256960,4096,163 84,256960
#Power Save Tweak
ro.ril.disable.power.collapse=1
pm.sleep_mode=1
wifi.supplicant_scan_interval=180
windowsmgr.max_events_per_sec=280
debug.performance.tuning=1
video.accelerate.hw=1
#MEDIA TWEAKS
media.stagefright.enable-player=true
media.stagefright.enable-meta=true
media.stagefright.enable-scan=true
media.stagefright.enable-http=true
media.stagefright.enable-record=false
ro.media.dec.jpeg.memcap=8000000
ro.media.enc.hprof.vid.bps=8000000
ro.media.enc.jpeg.quality=100
#SYSTEM TWEAKS
ro.HOME_APP_ADJ=1
dalvik.vm.heapsize=64m
ro.config.hwfeature_wakeupkey=0
ro.telephony.call_ring.delay=800
ro.lge.proximity.delay=25
mot.proximity.delay=25