1.Fota mode upgrade: through mobile phone settings-(general)-about equipment-system update (or software update)-update.
Precautions for upgrading firmware in this way:
1). The mobile phone needs to be set to the current time.
2). It is recommended that the mobile phone should be fully charged when upgrading, preferably above 50%.
3). The mobile phone should have enough storage space (at least 1GB USB memory).
4). The network environment is stable (the updated version of the system/firmware is large, which may consume more traffic, so it is recommended to use it when upgrading.
3. Send to Samsung Service Center for upgrade: Bring purchase invoices, maintenance cards and machines to Samsung Service Center, and professional after-sales engineers will help upgrade.
Note: the old version of the mobile phone may run slowly if it is updated with the latest version.