Skip grub installation or change disc

[Qqmike]

S-K, thanks for that info, it's good to know. When I wrote all those UEFI how-to's, I tried to cover all sorts of complex configurations of drives and ESPs and multiple OSs. Tested them.
I experimented and consulted Rod Smith on some issues (by email and a small donation ).
I'm glad to hear that the Calamares is doing some of this better.
Now that I'm done writing UEFI-booting how-to's, I have greatly simplified my personal PC use: 1 drive, 1 operating system (Kubuntu LTS!
Thanks again for updating me on this stuff. 👍 😊

[Schwarzer Kater]

[…]
At least on the previous Kubuntu installer (before Calamares), when you deal with more than one ESP, when installing an OS into one of the ESPs, you should turn the other ESPs off by temporarily turning off the boot flag on them.
[…]

Luckily this is not necessary anymore with the Calamares installer!
At least not if the EFI system partitions are on different drives.

Addition:
Multiple EFI system partitions on the same drive are not explicitely allowed or forbidden in the UEFI specifications - therefore various UEFI vendors may handle this differently.
This is the reason why I only use one single ESP per drive as a rule of thumb. In my experience/my tests in most cases it has worked just fine to have multiple ESPs on the same drive if need be, though.

[shishimaru]

I ended up by using the old EFI partition and, just to be sure, creating a /boot partition in ext2. Both in the internal SSD #2. Of course I ended up losing the possibility to boot the old Kubuntu but, well, it means that it's time to move on

It's still a huge mistery for me how these boot loaders and efi partition works. I literally spent the whole day yesterday, from morning to late night, figuring out how to make everything work, and I haven't found any consistent and precise result.

Thanks everyone so far, and thank you Qqmike too for your input I tried to ask other "sources" too, but I never received any kind of answer but some quick and rude ones.It's heartening to see that some good old community remained.

[Qqmike]

Just to interject something, though I'm not sure it is (still) relevant to where you are at.
At least on the previous Kubuntu installer (before Calamares), when you deal with more than one ESP, when installing an OS into one of the ESPs, you should turn the other ESPs off by temporarily turning off the boot flag on them.

Ex.: You have 3 ESPs somewhere on n disks, say ESP1, ESP2, ESP3. You are going to install Kubuntu using ESP3. First, use a partition editor to remove the boot flags on ESP1 & ESP2. Then proceed installing Kubuntu using ESP3 (so the installer doesn't see ESP1 and ESP2). After doing so, you might reboot and test your new Kubuntu to see if it boots ok, then turn on all the other ESPs (by turning on their boot flags).

[shishimaru]

You can do a manual partition install, and tell the it to use that for /boot/efi - it won't wipe any contents if you make sure the format option for it is un-checked.
Windows' boot files won't be touched, so you won't lose anything. You will get the warning about the 300mb, but that is fine if your Windows efi is only 100Mb - it uses about half of that, and Kubuntu will use iirc a few Mb (under 10)

You can also point it at your existing Kubuntu efi, and set it the same. However, in this case since they are both the same OS, with files in the exact same places, the 24.04 install will overwrite the existing grub files -- this is not a bad thing, as one grub can boot All The OSs
The only issue that can come up is when there is a kernel update in the older Kubuntu, it will reconfigure grub, and overwrite the newer one. And vice versa on the 24.04. This probably won't be a problem other than boot order, and the defualt OS switching around.
Some people (who know what they are doing) do use One Grub to Rule Them All.
Me, I prefer not to dual boot but when I do, I do like having each OS with its own grub. I would use Window's existing efi for the new install. so that I can have that for all three operating systems.
(I would also strongly push to using a USB stick/external drive. I am going to strongly bet that you will be doing so as soon as it is feasible due to frustration, very poor speed, extremely crappy reliability, and relatively quickly killing a few sdcards. Been there, done that many, many times )
This way, in a bad situation, I can still boot to another OS by selecting a different one via the system's bios boot menu hotkey.

Booting multiple *buntus on the same system adds a little bit of complexity, but nothing awful. it this were something like Fedora, Mint, or anything non Ubuntu, you would use either efi partition as desired.

Oh, it shouldn't be much of a hassle. I can just use the F11 key so that I can choose which hard drive will boot. If Windows' drive, Windows boots. If 2nd drive, then GRUB appear and I can use Kubuntu. I can also see that Windows can still be selected despite the fact that I installed Kubuntu with another EFI partition. Maybe it won't work if I select Windows, haven't tried yet.

For now, before you replied, I have tried to:
- install Ubuntu on microSD with its own EFI + install GRUB on 2nd SSD. Ubuntu appears in GRUB, but it doesn't find the kernel.
- install Kubuntu " ". Despite the fact that I used a separate EFI partition, it cannot be found in GRUB.

I think that Calamares is not letting me install GRUB again on SSD #2, and that's why the new Kubuntu is not found.

At this point, I can pray the heavens and totally remove Kubuntu and just reinstall it on one partition on the MicroSD EFI partition will stay on SSD #2 just to be sure. For the GRUB installation, I have zero idea of how to choose the path. If it follows the EFI partition, it will directly go to SSD #2. Otherwise, I don't know. Sighhh, it wasn't this complicated ten years ago with an older laptop, no UEFI and Ubiquity letting me choose everything, hahaha

[claydoh]

the first one has WIndows with its partitions and boot loader. I really wish to keep it this way

You can do a manual partition install, and tell the it to use that for /boot/efi - it won't wipe any contents if you make sure the format option for it is un-checked.
Windows' boot files won't be touched, so you won't lose anything. You will get the warning about the 300mb, but that is fine if your Windows efi is only 100Mb - it uses about half of that, and Kubuntu will use iirc a few Mb (under 10)

You can also point it at your existing Kubuntu efi, and set it the same. However, in this case since they are both the same OS, with files in the exact same places, the 24.04 install will overwrite the existing grub files -- this is not a bad thing, as one grub can boot All The OSs
The only issue that can come up is when there is a kernel update in the older Kubuntu, it will reconfigure grub, and overwrite the newer one. And vice versa on the 24.04. This probably won't be a problem other than boot order, and the defualt OS switching around.
Some people (who know what they are doing) do use One Grub to Rule Them All.
Me, I prefer not to dual boot but when I do, I do like having each OS with its own grub. I would use Window's existing efi for the new install. so that I can have that for all three operating systems.
(I would also strongly push to using a USB stick/external drive. I am going to strongly bet that you will be doing so as soon as it is feasible due to frustration, very poor speed, extremely crappy reliability, and relatively quickly killing a few sdcards. Been there, done that many, many times )
This way, in a bad situation, I can still boot to another OS by selecting a different one via the system's bios boot menu hotkey.

Booting multiple *buntus on the same system adds a little bit of complexity, but nothing awful. it this were something like Fedora, Mint, or anything non Ubuntu, you would use either efi partition as desired.

[shishimaru]

Thank you so much peeps!

I haven't used the same EFI partition yet just because I was very afraid and ignorant, so that's why I was trying to understand the situation better.

I should explain better my context:
- I have two internal SSDs
- the first one has WIndows with its partitions and boot loader. I really wish to keep it this way
- the second one has Kubuntu with GRUB and it has its EFI partition too, that automatically was created. I understand that the EFI partition could be avoided and the old Windows one could be used instead (maybe). Also this might be erased since...
- ...I have an external drive that cannot boot (SD reader, cannot use USB). I think that now I should: use a new partition EFI partition on 2nd SSD (so that the first Kubuntu can be bootable and eventually removed along with its own EFI partition to keep things clean), install GRUB on 2nd SSD. This is the hardest part since calamares doesn't allow to choose the disk in which GRUB will be installed. This way, the new Kubuntu should be "bootable" with the internal SD reader.

Do you think this is correct? ^^'

Also, I will 200% use the "Essential things to do after installation" topic since I will start from a minimal Kubuntu installation. I see that I can easily install the codecs with one of those. I am also thinking of using btrfs with a non-strong compression.

[claydoh]

......

[Schwarzer Kater]

Welcome.

Did you try selecting the "Manual partitioning" option of the installer? And then why not use the already present EFI system partition (without formatting it !) and new partitions for "/" and whatever else you want new partitions for? It will be the GRUB 2.12 boot loader of Kubuntu 24.40 LTS afterwards, though.

If I remember correctly one can only install no boot loader in Calamares for UEFI systems, if one modifies Calamares' Python settings files in the live mode before installation.
With "legacy" BIOS one can choose to install no boot loader after assigning "/"and other partitions (in "Manual partitioning").

After a sucessfull installation you might also be interested in Essential and strongly recommended things to do directly after a Kubuntu 24.04 LTS installation

[claydoh]

therwise I should create another boot efi on the internal SSD (meaning that I'd have 2 of them)

yes, you can have more than one efi partition, or just use one - you can have multiple OS installs in one EFI.

HOWEVER, a new kubuntu install using the same EFI will overwrite the existing Kubuntu one.

If you already have two efi's (one for windows and one for Kubuntu), you can point the microsSD install to use the Windows efi partition in the partition tool - just do NOT FORMAT it. Again, you can have more than one OS share this.
I am not sure if you can skip the efi or not - you do get a warning, but not sure if it will let you proceed or not. It has a new installer.
The old one iirc can skip it, using a command line switch. Haven't located any good info for this in Calamares yet.

[shishimaru]

Hello beautiful peeps.

I have already installed Kubuntu on an internal SSD of my laptop, with a separate /boot/efi fat32 partition.

I also want to install Kubuntu on a large microSD, but this is not bootable by my laptop (I already tried) and the USB card reader is not an option at the moment.

I wonder if I can skip the separate boot efi partition, install Kubuntu on /, and use the old Kubuntu's GRUB to boot into the new one. At this point I wonder: how to skip the GRUB installation or how to choose to install GRUB on a different disk?

therwise I should create another boot efi on the internal SSD (meaning that I'd have 2 of them). But I'm still worried about having two efi partitions and the old Kubuntu installation.

Any suggestion would be appreciated.