It is always nice to open a support thread for things which is a hot topic right now and gets even discussed for days by now …
So here again:
-
/etc/default/grubneeds to been checked forGRUB_PRELOAD_MODULES="cryptodisk part_gpt part_msdos"andGRUB_ENABLE_CRYPTODISK=y - grub menu needs to been updated via
update-grub
That should be the only thing you may need. Installing grub to MBR/UEFI always should be the last resort unless you want to have security updates or the latest grub version on your system. If your system however has a broken bootloader installation you may need to restore it. Read the linked discussion thread for more info about further solutions.