'non-upgradable' originates from Modern English, composed of the negative prefix 'non-' (from Latin 'non' meaning 'not') and 'upgradable' (derived from the verb 'upgrade' plus the adjectival suffix '-able', where 'upgrade' combines 'up' and 'grade').

'upgrade' developed in Modern English by combining 'up' (Old English) with 'grade' (from Old French/Latin 'gradus'), then formed 'upgradable' with the suffix '-able'; 'non-upgradable' is a later productive formation using the prefix 'non-'.

The component parts originally meant 'not' + 'able to be upgraded'; combined as 'non-upgradable', the phrase has largely retained that straightforward negative meaning of 'cannot be upgraded'.