Something relevant is obviously changed in the kernel >= 4.10.x,
be it upstream or downstream,
considering that Secure boot works seamlessly with the kernel <= 4.9.x.

Actually, secure boot doesn't work since a bug in grub causes the secure boot flag worked out in the efi boot wrapper to get sanitised away before the main kernel gets to see it.  See bug 1418360.

(In reply to David Howells from comment #2)
> Actually, secure boot doesn't work since a bug in grub causes the secure
> boot flag worked out in the efi boot wrapper to get sanitised away before
> the main kernel gets to see it.  See bug 1418360.

Thank you for your response, I left a comment there.

*** This bug has been marked as a duplicate of bug 1418360 ***

This bz isn't really a duplicate of the grub bug.  The error message you have an issue with is from the kernel's EFI boot wrapper, saying that it can't manage to determine the secure boot status from the UEFI BIOS.

What happens in the kernel is:

 (1) The EFI boot wrapper stores a flag in boot_params to note the outcome of the secure boot mode determination.  This is where the "EFI stub: ERROR: Could not determine UEFI Secure Boot status." is emitted.

 (2) The decompressor calls sanitize_boot_params(), which sees that the boot_params were incorrectly set up by grub and clears parts of boot_params, including the secure_boot flag.  This is bug 1418360.

 (3) In the main kernel, setup_arch() looks at the flag and sees the cleared value.

This bug is related to https://bugzilla.redhat.com/show_bug.cgi?id=1418360
therefore it remains open until the origin resolves.

Ref.
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/drivers/firmware/efi/libstub/secureboot.c

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