Grub problem with new installation Mint 20.2 dual boot - two drives

[hag6]

Absolutely right the drive names had changed sdd is now sde and sbd has changed to sdc

I tried to install grub on sde it completed ok. Rebooted, selected sdc via boot menu but no grub - 20.02 loads. I can only get 20.02 grub by holding down the Shift key. The grub only lists 20.02.

When sde is selected via boot menu, it boots to grub listing 19 & Win7, So I am back to square one

[AndyMH]

When sde is selected via boot menu, it boots to grub listing 19 & Win7, So I am back to square one

Is this with LM19 top of the list and no LM20 showing? If so, boot into LM19 (which is what I think you should get having re-installed grub to sde when booting sde) and sudo update-grub, should find LM20 and add it to the grub menu.

I tried to install grub on sde it completed ok. Rebooted, selected sdc via boot menu but no grub - 20.02 loads.

As above, with you selecting sdc (now with grub on it pointing at LM20) and getting LM20. In LM20 sudo update-grub and it should find the other OS. I had assumed that installing grub to what was sdb now sdc would mean it would automatically search for other OS and add them to the grub menu, apparently not.

Think you have a desktop, it might make life easier if you swap the sata cables around so that what is currently sde (LM19/win7) is on sata port 0 and your LM20 drive is on port 1 (or the other way round). This is speculation and on the basis that if you have those drives on the first sata ports it maybe less likely that the devices names will change. More likely to appear as sda and sdb consistently.

In 'normal use' on my thinkpad T430:

• sda = main drive bay (in BIOS = HDD0)

• sdb = ultrabay = DVD drive, but now a 2TB HDD for backup (in BIOS = HDD1)

• sdc = msata ssd (my boot drive, I use sda for testing software with other OS). In BIOS = HDD2.

But at the moment, with an HDD plugged into a usb port via a sata/usb adapter:

• sda = unchanged

• sdb = the usb drive

• sdc = ultrabay

• sdd = msata ssd.

Confused the hell out of me when I first noticed it, but now I understand what is happening, if I need to do anything that requires specifying the device, e.g. sdb, I check first. The BIOS 'allocations' remain unchanged, e.g. my msata is always HDD2.

[hag6]

Thanks for your continuing help. I really appreciate your time. I have taken your advice and plugged the two boot drives into Sata0 & Sata1 as recommended.

For the time being, I will have to move across the two drives via the boot menu for now as it seems that “fusing” the two grubs into one is not an easy option (if at all possible). The main reason for installing 20.02 on a new drive was to avoid the original dual boot drive from failing by becoming too full (its only 128gb).

If I reinstall 20.02 again how could I link/fuse it to the existing dual boot drive? I did select “Something else” when I installed it but don’t remember being offered any grub options.

Not sure what may have caused this problem with 19.3 Suspend no longer works. When resuming the system, the screen doesn’t offer the sign-in box. The screen is a pale and frozen. Only a complete restart gets me back.

Suspend doesn’t work every time with 20.02. Not frozen - I can access the system but on occasion one data drive is not available. Again I have restart to get full access. Not sure if this just a glitch or I need to reset something.

[AndyMH]

Don't use suspend so can't help with that.

sudo update-grub should fix it. The normal reason it doesn't work is if one OS is installed in legacy mode and the other UEFI or vice-versa, but your os-prober output showed it was finding the other OSes, so mystified if you haven't tried to update grub. Moving your drives around to different sata ports should have no impact. grub uses the UUID of the partition when picking which partition to boot, this doesn't change.

When you install with 'something else' at the bottom of the screen is where you specify where to put grub:

this is probably the bit that you missed. You select the drive not a partition. With LM20 booting legacy it does what it is told, with UEFI boot it misbehaves (another story).

I dual boot LM - I have another copy of LM on my backup drive so I can boot into it and fix problems if I screw up the main drive. Installing LM to the backup drive (making sure it put grub on the backup drive) - it found LM on my main system drive automatically and added it to its grub menu. Booting from the main system drive I did a sudo update-grub and it found LM on the backup drive and added it to its grub menu.

[hag6]

Hi somehow it seems to have worked!

After several restarts I booted to 19.3 (sdb) and 20.20 was in the grub. The sda drive with 20.02 still reports no grub in terminal (but i can navigate to the file manually). However, when I select 20.02 to boot from the grub it doesn’t go to the sign-in screen directly but generates a scrolling set of data before finally setting up the sign-in screen. Also, the first time I booted, it didn’t mount any of the data drives. I had to restart to gain access to the data drives.


Many many thanks

[AndyMH]

We have all made similar mistakes, it's part of the learning experience