I have Ubuntu 21.04 installed on an external SSD, on an old iMac which is already set with dual boot Mac OS and Windows 10. I want to replace the Mac OS with Ubuntu. And if possible, I would like to use the content of the external SSD as I already set up Ubuntu with all the softwares I need.
The iMac have 8 Gig of memory, Intel Core I5-4570S CPU @2.90Ghz x 4
SSD 1 TB, partitions MacOS 400 GB, BOOTCAMP (Windows) 599 GB
(I should have made this 500 GB each)
Ubuntu: version 21.04, GNOME 3.38.5
Present external drive with Ubuntu is 500 GB (leaving 480)
PS: I’m not planning to never reinstall mac OS if this can help.
PS2: I’m scared of loosing Windows for the time being as it has everything I need on it. I’m planning to gradually move everything to Ubuntu and eventually, one day, remove Windows 10 to leave only Ubuntu.
I need to make the booting as smooth as it is between Windows and Mac OS. i.e. once I toggle to boot in Windows, every reboot starts in Windows. If I toggle to boot from MacOS, every reboot starts in Mac OS. I dont want to select the boot every time.
At the moment, to boot from Ubuntu, I have to connect a wired keyboard, hold the ALT key then turn on the power. Then, the boot selection appears, and I must select the yellow icon that saids WINDOWS to boot in Ubuntu.
I know I should backup Windows first, but that never garanties that restoring the backup will work. Sometime, the problem is related to boot sector, or any other things.
Can someone lead me into the right procedure?