My pc does not boot anymore in EFI/UEFI mode. I had grub installed and was able to boot on both Windows 10 and Ubuntu Linux (14.04 LTS). I recently tried to install Fedora Workstation 29 'automatically' making space from the ubuntu partition. Since then I have not been able to boot in EFI/UEFI. The boot process simply do not see the hard drive as an EFI boot disk. I have tried to remove the Fedora installation, I installed a new version of ubuntu and nothing works. I have tried to reinstall windows, but I cannot boot from window flash drive. I can boot from linux flash drives, and from there I can see the disk partitions (even if I can't mount the Windows partition as it seems to be in hibernation state). Is there any possibility to restore the machine in working state? What am I supposed to do? I have tried asking for help here and here with scarse success.
EDIT: I've been able to boot the local ubuntu disk with Super Grub2 Disk. It actually gave me access to the grub rescue terminal. From there I was able to:
this procedure gave me access to a set of bootable kernels, only the old ubuntu one is working. From ubuntu I mounted the windows partition
sudo mount -o remove_hiberfile /dev/sda4 /mnt/win
backup my windows and linux files.
Next step will be to format/reinstall Linux. From there I have to figure out how to reinstall Windows.