WIZARD'S RECOMMENDED READING
https://www.linux.org/threads/question-about-partitioning-sdd-after-os-is-installed.19701/
BACKGROUND
At the above link, Member Jeffrey has a laptop with two drives in it - a 256 GB Micron SSD (Solid State Drive) and a 1 TB Seagate HDD.
He is dedicating it purely to Linux use, and started off installing Manjaro 17 GNOME on it, which worked, on the SSD (/dev/sdb) and then went to install Linux Mint 19 'Tara' Cinnamon on the HDD (/dev/sdba).
Jeffrey is keen to try multibooting, and I can certainly appreciate that, lol.
We knew in advance what would happen, and that is this,
Effectively, Manjaro is a brilliant Distro, but it does not like to share with other Linux. This has been the case for some years now. It took us some time, together, to get his LM Cinnamon set up on the HDD, and the outcome, as was to be expected, is that he gets a Grub Menu featuring the new, Linux Mint, on top, with Manjaro as a 2nd choice.
The Mint works fine, but if you try to boot the Manjaro, it falls over with a Kernel Panic.
This will likely look something like this
SCREENSHOT 1 - MANJARO KERNEL PANIC
There is no way out of this screen other than to power down.
There is a short fix for this, and a longer-term fix and I am going to cover both here.
But (Wizard's But is always lurking, and sometimes juxtaposed with his head) - I want to get Jeffrey up and running with his 2nd distro asap, so we'll take the fast track, and then I will cover both options in more detail.
Short Fix next.
Wizard
https://www.linux.org/threads/question-about-partitioning-sdd-after-os-is-installed.19701/
BACKGROUND
At the above link, Member Jeffrey has a laptop with two drives in it - a 256 GB Micron SSD (Solid State Drive) and a 1 TB Seagate HDD.
He is dedicating it purely to Linux use, and started off installing Manjaro 17 GNOME on it, which worked, on the SSD (/dev/sdb) and then went to install Linux Mint 19 'Tara' Cinnamon on the HDD (/dev/sdba).
Jeffrey is keen to try multibooting, and I can certainly appreciate that, lol.
We knew in advance what would happen, and that is this,
Effectively, Manjaro is a brilliant Distro, but it does not like to share with other Linux. This has been the case for some years now. It took us some time, together, to get his LM Cinnamon set up on the HDD, and the outcome, as was to be expected, is that he gets a Grub Menu featuring the new, Linux Mint, on top, with Manjaro as a 2nd choice.
The Mint works fine, but if you try to boot the Manjaro, it falls over with a Kernel Panic.
This will likely look something like this

SCREENSHOT 1 - MANJARO KERNEL PANIC
There is no way out of this screen other than to power down.
There is a short fix for this, and a longer-term fix and I am going to cover both here.
But (Wizard's But is always lurking, and sometimes juxtaposed with his head) - I want to get Jeffrey up and running with his 2nd distro asap, so we'll take the fast track, and then I will cover both options in more detail.
Short Fix next.
Wizard