Ok, I'm on phone but will add as much detail as possible:
17.10, just upgraded, everything upgraded fine except shim-signed which failed. I presumed it would be ok, it wasn't.
/boot filled during upgrade despite having enough space according to the measurement at the start.
Hardware is MacBook air. Bought three years ago, have been updating version to version fine.
HD has encrypted /
/boot would constantly fill bc 200MB, I think I might have moved /boot/efi to /opt/boot/efi to make room, and symlinked back.
After upgrade to 17.10 reported a fail with msg to x or r, I made space probably by moving something else to /opt/boot. I can't remember.
Never occurred to me that this was an issue until now that I can't reboot and I realise that / is encrypted.
Anyway. Nothing is booting. I get grub rescue prompt.
On new boot set tells me: Cmdpath=(hd1,gpt1)/EFI/Ubuntu Prefix=(hd1,gpt2)/grub Root=hd1,gpt2
ls (hd1,gpt2) returns results, including grub (not a dir), and efi/ which is empty :( otherwise it's all vmlinuz, config, initrd, abi, a couple of System and memtest bin files.
insmod normal tells me: error: file /grub/x86_64-efi/normal.mod not found.
I guess I'm fubar'd, right?
I can reinstall, but I'd like to get data off. Except bloody encrypted drive. F