dd :запись в недопустимый аргумент с размером блока 4 КБ на iSCSI LUN

Используйте вертикальную черту перед каждым отдельно стоящим условием.

Со страницы руководства freedesktop:

If multiple conditions are specified, the unit will be executed if all of them apply (i.e. a logical AND is applied). Condition checks can be prefixed with a pipe symbol (|) in which case a condition becomes a triggering condition. If at least one triggering condition is defined for a unit, then the unit will be executed if at least one of the triggering conditions apply and all of the non-triggering conditions.