I used Option+Command+P+R to try and fix a sleep issue in OSX. From there I'm a little confused about what happened but I ended up in a mac recovery mode (offering to reinstall OSX), which I tried to exit out of as quickly as possible.
When it rebooted, it seems to be jumping straight to grub, which needs telling which partition to boot and I can't boot OSX (only Ubuntu).
It's as though I've changed the active partition (is that even relevant for EFI?). Can this be fixed from inside ubuntu? I have a retina display macbook, so no CD, and I'd like to fix this from inside Ubuntu ideally.