There are two files:
Both files are updated on the server once per day, usualy around 7:51(GMT+2).
They should be downloaded to the folder: /data/misc .
When you try to download them from phone "EPO settings", you see message "EPO FILE INFO DOWNLOADING", than you see (50%). That 50% status appears and disappears around 3 times, and some time after that you receive error message "Download files invalid".
The reason is, that they have always wrong MD5 checksum in file EPO.MD5. So your phone download and compare/calc checksum for few times, but every time the checksum is incorrect. And that is reason, why it is not working.
I have tried to connect to the epo.mediatek.com ftp server manually from PC. Every time i download EPO.DAT file, the MD5 checksum is the same, but in EPO.MD5 file is another one (also still the same).
I have calculated correct MD5 checksum, and changed it to correct value to the file EPO.MD5. Than I have uploaded both files to my private FTP server. And than, through "Engineering Menu" (you can enter there by calling number *#*#3646633#*#* and then select "EPO" item) in the phone I have changed FTP connection/login/password to my server, and tested that. And when I have there correct MD5 checksum in file EPO.MD5, everything works as it should be.
So someone should tell Mediatek, that they have some serious problem with MD5 calculation on their FTP server.