My 5800 applied for a certificate, but after using it to sign software, it prompted that the certificate had expired, and before adjusting the time, it prompted that the certificate was not valid.

The Nokia 5800\N97 operating system is S60 version 5. Since it is a relatively new system, many software does not support installation. If you install the signed software, it will display "The certificate has not yet taken effect, has expired, or the date is set incorrectly." Please perform a soft format first (format command *#7370#), restart, select the time zone and current date of where your phone was produced, and then install the software. This can generally solve the problem.

Tips: The format will lose all data, text messages, phone books, etc., please back up first.

The first step: Format the card (memory card) first, and make a backup before formatting; you can also just pull out the card if you don’t want to format it

Second Step: *#7370# Password 12345

Step 3:

If the machine is licensed in Hong Kong, select Hong Kong region (HONG KONG);

If so The regional version of the Asia-Pacific version of the software (check the language in the settings, if there is only English and Simplified Chinese, it is the Singapore version, if there is Malay, it is the Malay version),

Singapore is the Select Singapore after the soft grid,

If you are in Malaysia, select Malasiya, then adjust the date to the current time, reinstall the software, and it will be OK! Select Chinese and set the second one in the mobile phone

Step 4: As long as you use the S60V3 version certificate after soft format, it is universal.

The soft grid will turn into English. Here is how to select back to Chinese;

The solution steps are as follows:

1 Enter the desktop

2 Tools

3 Settings

4 General

5 Personalization

6 Language

7 Phone language

8 Select "Simplified Chinese"

Restart the machine OK