so ,recently i installed kali linux latest version on my laptop lenevo ideapad 320

when i was about to complete installation i faced a problem it said ''installing grub dummy failed'' .and then i continue without bootloader

it said like that..
" you will need to boot manullay with the /vmlinuz kernel on partion /dev/sda2 and root=/dev/sda2 quiet passed as kernel argument."

and from then i am booting manually every time .I tried running boot -repair disc , it said "locked NVram detected "
help me guys i am new to community!!
i also tried this...

sudo grub-install /dev/sda
[sudo] password for kali:
Installing for x86_64-efi platform.
grub-install: warning: Cannot set EFI variable Boot0004.
grub-install: warning: efivarfs_set_variable: writing to fd 6 failed: Interrupted system call.
grub-install: warning: efivarfs_set_variable: failed to unlink /sys/firmware/efi/efivars/Boot0004-8be4df61-93ca-11d2-aa0d-00e098032b8c: Invalid argument.
grub-install: warning: _efi_set_variable_mode: ops->set_variable() failed: Interrupted system call.
grub-install: error: failed to register the EFI boot entry: Interrupted system call.