I recently changed my passphrase through 'Disks' and I've included the character £ in it. I realise now that the UK keyboard mapping only applies after this is done, so trying to type £ gives me # instead (I'm assuming, I can't see the password).
How do I type £ at the screen 'cryptsetup: please unlock disk'? None of the AltGr+Number or Shift+Ctrl+Something I've looked up seems to work, apart from sometimes shutting off the screen. (e.g. when I press down one of the arrow keys. Why is that?)
Hopefully this won't need any personal technical details but if it does I'll put it here.
Best Answer
Setup keyboard/locale in initramfs
/etc/initramfs-tools/initramfs.conf
KEYMAP=y
sudo update-initramfs -u
Ref: How to set keyboard layout in initramfs
Workaround
/dev/sda2
sudo cryptsetup luksAddKey /dev/sda2