[SOLVED] After installation no Grub2

[facciofinta]

I've installed SparkyLinux (Dual Boot with an Ubuntu Studio partition and a Windows partition).
At start the grub2 is not founded.
I could access to all the OS thanks to Super Grub2 Disk https://www.supergrubdisk.org/super-grub2-disk/ but how can I repair the grub?
Here the info thanks to GParted:

[facciofinta]

Can I use the SparkyLinux live USB to boot in EFI mode and reinstall Grub?
cfr. https://wiki.debian.org/GrubEFIReinstall

[verndog]

Another great grub fixer program I've used is rescatux:
https://www.supergrubdisk.org/rescatux/

[facciofinta]

This worked for me:
Download rEFInd boot manager at http://www.rodsbooks.com/refind/getting.html
I've chosen the "USB flash drive image file" of rEFInd
Then find your usable usb-stick

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sudo fdisk -l
For me it was detected

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Disk /dev/mmcblk0: 1,9 GiB, 1973420032 bytes, 3854336 sectors
unmount it

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umount /dev/mmcblk0
copy the .img file of rEFInd

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sudo dd if=/home/USER/ETCETERA/refind-flashdrive-0.12.0/refind-flashdrive-0.12.0.img of=/dev/mmcblk0
then restart computer with boot option to the UEFI on that usb-stick
now navigate the beautiful rEFInd panel - look for "install rEFInd on your computer"

that's it!

[paxmark1]

I sometimes check howtos for age and appropriateness

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aptitude show refind
Package: refind                         
Version: 0.11.3-1
State: not installed
Priority: optional
Section: admin
Maintainer: Rod Smith <rod.smith@canonical.com>
Architecture: amd64
Uncompressed Size: 4,654 k
Depends: debconf, efibootmgr, openssl, parted, debconf (>= 0.5) | debconf-2.0
   ...

nice find.  web page was updated in March of 2020  It is in debian repositories, so vetted.  I choose to not help with grub2, one can only do so much.