8f2babd032 was partially reverted by mistake. Original message below
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On some systems, EFI variables are not supported or otherwise wonky.
bootctl attempting to access them causes failures during bootloader
installations and updates. For such systems, NixOS provides the options
`boot.loader.efi.canTouchEfiVariables` and
`boot.loader.systemd-boot.graceful` which pass flags to bootctl that
change whether and how EFI variables are accessed.
Previously, these flags were only passed to bootctl during an install
operation. However, they also apply during an update operation, which
can cause the same sorts of errors. This change passes the flags during
update operations as well to prevent those errors.
Fixes https://github.com/NixOS/nixpkgs/issues/151336