My board is not booting.


I have an UP board that after several months of uninterrupted use, is not booting now. It's is possible that the RTC battery was unpluged (I'm not sure). What I can say is:

1. eMMC is not shown as F7 boot option (despite it apears in Chipset>South Bridge eMMC: Unknown M52516...(14.5 GB) )
2. It always loads directly to the password prompt to enter BIOS.
3. It seems unable to enter to EFI Shell.
4. The date/time is lost. If I set it, it gets lost after power cycling. However the battery voltage is 3V, and it seems adequately connected.
5. Reseting BIOS by unpluging the battery doen't help.

I hope you could give me some advices to bring the board back to life.

Thanks for your help.