Automatically updates the EPO.DAT file on the Fairphone 1 within a given interval (defaults to 5 days). This fixes the 'EPO update failure' problem permanently, so no need to update it manually every 30 days. For information on why EPO.MD5 isn't fetched as well, see 'Background' below.
You need to have EPO enabled first (in System Settings or EngineeringMode).
Download and run the app, click on 'Enable' and allow permanent root access.
If an update is required, it will be downloaded now. This may take a minute and you will see notifications while this happens.
Wait for the status bar to become green and to display the current time.
Disable the original 'Auto download' to avoid problems (in System Settings or EngineeringMode).
Fairphone FP1 with the 'Stock Android' and busybox
Alcatel Onetouch 997D with Android 4.1
Needs root access in order to write the new EPO.DAT to /data/misc and to adjust permissions.
For EPO to work, only the EPO.DAT file is required. The EPO.MD5 is only a checksum to validate the correctness of the EPO.DAT file after download. In principle, it is a good idea, to do so. However, in this case, the .MD5 checksum is also a bit the source of the problem: The built-in EPO updater of the Fairphone (or other Mediatek phones) downloads the two files from an FTP server from Mediatek. Unfortunately, the .MD5 checksum is often calculated wrong by Mediatek. Therefore, the check of the .DAT file fails and the 'EPO update failure' occurs. See also this post: http://forum.xda-developers.com/showthread.php?t=1975500