LG E420 Guide De L'utilisateur page 420

Phone software update
NOTE: Your personal data from internal phone storage—including information
about your Google account and any other accounts, your system/application
data and settings, any downloaded applications and your DRM licence—
might be lost in the process of updating your phone's software.Therefore,
LG recommends that you backup your personal data before updating your
phone's software. LG does not take responsibility for any loss of personal
data.
NOTE: This feature depends on your network service provider, region and
country.
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