@madisongh has added some changes to support cboot related boot on NVIDIA related platforms in https://github.com/Trellis-Logic/meta-mender-community/pull/10. A portion of these changes are related to interoperability with non u-boot based platforms, which is implemented by fake stubs of fw_printenv and fw_setenv utilities.
In the cboot case we don’t need any support for bootloader environment configuration from the mender utility, since NVIDIA boot redundancy handles this for us, and nvidia utilities are being invoked from mender update hooks.
I wondered if the fake fw_printenv/fw_setenv approach is the approach we should use for zeus support, or if we should instead propose changes to the mender utility to support externally configured boot environment variables. The main reason to officially support externally configured boot environments would be to avoid issues going forward if anything changes regarding u-boot environment support in the mender utility.