I have a computer with two internal hard disks. Initially, Ubuntu 16.04 was installed. I installed Ubuntu 20.04 on the other hard disk so I could gradually migrate everything. I have finished the migration and and happy with 20.04 and am ready to delete the partitions used for 16.04. But I am very inexperienced and nervous about doing this, so am asking here for the precise steps to take so that I don’t screw up my 20.04 installation.
Here are the current partitions:
/dev/sdb – where 16.04 was initially installed
/dev/sdb1 – EFI System; 537 MB; FAT32
/dev/sdb2 – Ext4; 991 GB (encrypted)
/dev/sdb3 – Swap
/dev/sda – where 20.04 was installed
/dev/sda1 – EFI System; 537 MB; FAT32
/dev/sda2 – Ext4; 991 GB (not encrypted)
I obviously want to keep /dev/sda2 and want to replace the encrypted /dev/sdb2 with some other partition. I have no idea what to do about the two EFI partitions. I presume, but am not entirely sure, that the Swap partition is being used by both 16.04 and 20.04, so it should be left alone.
So, any help in the precise applications and steps to use to achieve my goal, which is to completely remove 16.04 and boot directly to 20.04, would be very much appreciated.