Groovy Gorilla (20.10) is currently planned for release on October 22, so we'll need to release Rufus 3.12 before that date to fix the following:

• [a8f3c6c] Regression, introduced in 3.11 (in commit 77d3192), that prevents proper GRUB binary parsing to find the GRUB version. → Initial analysis indicates that this could be due to looking for i386-pc as a subdirectory, but getting I386_PC internally, i.e. we may have broken ISO9660 name translation.
• [e987272] error: symbol 'grub_calloc' not found when using our current GRUB bootloader and booting in BIOS mode. → This appears to be a result of Ubuntu using an updated GRUB 2 bootloader that includes the fixes for GRUB2 UEFI SecureBoot vulnerability 'BootHole' and more specifically this patch. Hopefully, recompiling our GRUB downloadable binaries from latest source should be enough to fix this, though it's very possible that this may introduce a regression with older GRUB modules...
• [2d272b7] Oh great, the switch of Syslinux to GRUB means our md5sum update doesn't run, which result in a checksum mismatch during boot for drives with persistent images. Will have to fix this.

Also, in a amazing level of short-sightedness, the Ubuntu maintainers have decided to do away with placing the EFI boot loaders on the ISO file system, and instead chose to shove them into /boot/grub/efi.img. How the heck someone came to thinking that this made any shred of sense is absolutely beyond me.