Strange Grub update issue

[black-clover]

I have a main VL-7.2-STD distro on my laptop and a spare partition which I use to try different distros that pick my fancy.
Twice, on different distros that I have installed (Calculate Linux and Manjaro) I had a strange problem.
After running update-grub on my main VL distro, the newly installed distro had problems at booting, once systemd didn't couldn't load the kernel modules and another dracut was erased.
If I reinstalled the distro and did not run update-grub, and leave the old entry with the proper kernel name, it would work just fine.
Therefore, I deduce that the problem is with updating grub.
By the way, this did not happen if on the spare partition in installed VL, only with other distros.
Is there any issue with updating Grub which I should take into account?

[retired1af]

Depending on your machine and whether it has UEFI activated or not, you may need to use a "signed" version of Grub. When I install VL, I do not install the bootloader and use Mint's signed copy of Grub instead.

[black-clover]

thanks for the answer,  but what is a "signed" version of grub? 

[retired1af]

With Secure Boot, the bootloader must be "signed" with a digital key that's contained in the firmware.

Here's a bit of a "how does it work".

https://askubuntu.com/questions/874584/how-does-secure-boot-actually-work

[black-clover]

hi,
I checked the BIOS system setup on my laptop, and it doesn't have an option for the "secure boot" or enabling UEFI as I've seen on other (newer) laptops.
I've read the post you pointed out but I still don't understand if I can set up grub to provide the signature at the update or if I have to deal with the issue with the systemd config on the newly installed distro.

[retired1af]

You shouldn't need to worry about the "signed" bit then.

Have you tried grub-probe?

[black-clover]

I've been trying several distros lately on a spare partition and some of them (Manjaro, Calculate Linux, Fedora, Arch Linux) have problems after the Grub update.
My inexpert solution was, if the test distro used systemd, to install its own Grub the test distro /.
The VL Grub would point to the new Grub and this would boot the test distro.
That way I didn't have any problem, not elegant perhaps but it did the trick.