Function update_boot_parameters 

pub async fn update_boot_parameters(
    infra: &InfraContext<'_>,
    token: &str,
    params: UpdateBootParametersParams,
) -> Result<(), Error>

Replace the BSS boot-parameter record for params.hosts with the values carried in params.

The caller’s access to every host is validated first. cloud_init is intentionally left unset: the update endpoint accepts only the core boot fields (params, kernel, initrd, macs, nids).