Android source code to modify the time zone method

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How to change the default time zone Android system. (Source code modifications)

Tried to find online method will not work do not know why

For example: 5 to modify build / tools / buildinfo.sh:
echo "persist.sys.language = zh"
echo "persist.sys.country = CN"
echo "persist.sys.localevar ="
echo "persist.sys.timezone = Asia / Shanghai"
echo "ro.product.locale.language = zh"
echo "ro.product.locale.region = CN"

The result is the language changed, but not changed time zones, and who knows why Well

Who is a better way to do

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Reply:
Directly in the "Setting" which can be set
Reply:
persist.sys.timezone = Asia / Shanghai this value does not seem right, what is the value of the next argument there. . .
Reply:
android how to modify the default factory default date and time zone

Reference. RuntimeInit.java changes mainly in parts.
Reply:
Value
look out the timezone of the following build.propSuspected multiple mk file defines timezone
Reply:
At first a change of time zone in New Delhi, India, causing me to night, Forget the past
Reply:
Really have to get inside device.mk file already defined value persist.sys.timezone of the
So I have does not work after adding
Thank you for your answer