@Norbert_X, when I do sudo kpartx -a -v ~/ubuntu.raw, I see output as
add map loop20p1 (253:0): 0 1048576 linear 7:20 2048
add map loop20p2 (253:1): 0 30406623 linear 7:20 1050624
but if I do losetup, it only lists /dev/loop20 not loop20p1 and loop20p2. So, I am not able to proceed with formatting as given in the next step. I get following error.
mkfs.fat 4.1 (2017-01-24)
mkfs.vfat: unable to open /dev/loop20p1: No such file or directory
What am I missing? My plan is to create 512M for EFI and rest for /.
EDIT: Please discard the query. Will keep the post so that other who may do same oversite as me would know.
I was supposed to use /dev/mapper/loop20p1 not /dev/loop20p1.