Issue #2778
The "create_grub2" script functionality is moved to the g2fg contrib sources
and also the GRUB2 head image (tool/grub2-head.img). The head image is now
partitioned as GPT and bootable in BIOS legacy mode.
The mkfs.ext2 heuristics select the "small" ext2 usage type, which does
not fit well with GiB-sized pen drives. For example, the block size is
just 1024 bytes compared to 4096 for "default". Therefore, we enforce
the default usage type as this fits our use case of dumping the image to
USB sticks better.