eMMC not detected

I have been using the UP board (4/32GB) for a few months now without problems, but since yesterday it has been unable to boot (goes straight to EFI shell).

The problem started after I had turned it on by accident and turned it off by holding the power button (during the UP splash screen). I booted from an Ubuntu live USB stick, but it could not find any other storage than the USB stick itself.

I have tried resetting the BIOS settings and unplugging the RTC battery, but it didn't help. After looking through the BIOS settings and noticed that under Chipset->South Bridge it says eMMC: Not Installed / Disabled, even though the SCC eMMC Support setting is set to ACPI mode (which I assume is the default).

Any ideas, or is the eMMC fried?