Dual Booting with separate Drives

Ok, evidently "jumped the gun";
Setup:
nvme0n1p1 (2T EVO980Pro)- Zorin 17 Pro/LTS(?) installed (aka "C:" drive)
nvme1n1p1 (2T EVO970Plus) - Win10pro64 installed (aka "D:" drive)
Assumed (and we all know what they say about "assume")
that, somehow, miraculously, GRUB would detect second OS is present.
Evidently not.
to keep OSs "isolated", used "F12" at boot (to select boot drive)
A bit clumsy, but, tolerable.
...unless I'm missing something (?)
btw,
Also have additional SSDs installed
(for other, large files, .jpg .pdf, etc... file formats that both OSs can work with)
Those SSDs have been formatted as NTFS (vs. Ext4 - Ubuntu standard)
IFAIK, windows does not "recognize" Ext4" formatted drives
Ubuntu can work with both formats (i.e. Ext4 and NTFS)
(yeah, yeah, I know Ext4 is "faster"...)
Furthermore, many hardware updates (i.e. firmware) are only available via windoes...
Example: Samsung Magician.
sceptical with doing this via "wine".

If there is a fix, groovy, if not, can live with BIOS/"F12" alternative

BTW, "FAT (32-bit version)"?? vs. 64-bit?

p.s. as a rule, I always do new installs on new drives; saving the original drive to re-boot, should I want to go back and find old data. (still have a shoebox full of IDE drives... even some original "floppies" :wink:
John

Hello John57,
I had a similar problem and was able to solve it with the help of @NxtMighty.
Here is the link to the thread:

Installing Zorin OS on a computer with multiple SSDs

In the BIOS, the topmost data carrier must be the one on which Linux is installed – in my case, it says "ubuntu". The Windows boot manager is only in second position.