It seems that under Casper installation GUI, the menu item of parition type of Reserved BIOS boot area (a.k.a. biosgrub) is no longer available in Ubuntu 20.04.[45] at the stage of partition planning. To fix this, we can preset the 1MB partition type of /dev/sda2 as do not use the partition during partition planning, then change its type code to EF02 later before confirmation of the timezone selection.

	Ubuntu 20.04.[45] (in class)	Ubuntu 20.04.3 (in the video)
Preliminary partition plan under GUI:
Preliminary partition plan reported by: gdisk -l /dev/sda
Fix	After you select the timezone but BEFORE clicking "continue", open a terminal and do: sudo gdisk /dev/sda p    # print partition list of /dev/sda t    # change partition type 2    # change type of partition 2 ef02 # change type of 2nd partition to EF02 (BIOS boot) w    # write change y    # confirm change (y/N) and quit gdisk then continue installation under GUI.	No fix required.
After Fix		—