Add a default root access mode from CyanogenMod https://github.com/CyanogenMod/android_vendor_cm/commit/127ac8a44e93b6966adc32860f4c5fad211585ec
diff --git a/products/common.mk b/products/common.mk
index 5d30165..36dcbe9 100644
--- a/products/common.mk
+++ b/products/common.mk
@@ -42,6 +42,7 @@
 	start-ssh
 
 PRODUCT_PROPERTY_OVERRIDES += \
+    persist.sys.root_access=1 \
     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 \